IT


Line plots across dimensions of each concept
Tables

Table of contents



us-gaap:CommonStockValue

us-gaap:CommonStockSharesIssued

us-gaap:CommonStockSharesAuthorized

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic

us-gaap:EarningsPerShareBasic

us-gaap:EarningsPerShareDiluted

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax
us-gaap:ProductOrService
us-gaap:StatementBusinessSegments
us-gaap:StatementBusinessSegments, us-gaap:TimingOfTransferOfGoodOrService
us-gaap:StatementGeographical
us-gaap:StatementGeographical, us-gaap:StatementBusinessSegments
us-gaap:TimingOfTransferOfGoodOrService

us-gaap:Revenues
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:CostOfGoodsAndServicesSold
us-gaap:ConsolidationItems

us-gaap:CostsAndExpenses

us-gaap:SellingGeneralAndAdministrativeExpense
us-gaap:ConsolidationItems

us-gaap:OperatingIncomeLoss
us-gaap:ConsolidationItems
us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:InterestExpense

us-gaap:OtherNonoperatingIncomeExpense

us-gaap:OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax

us-gaap:IncomeTaxExpenseBenefit

us-gaap:ComprehensiveIncomeNetOfTax

us-gaap:NetIncomeLoss
us-gaap:StatementEquityComponents

us-gaap:Assets

us-gaap:Liabilities

us-gaap:LiabilitiesAndStockholdersEquity

us-gaap:StockholdersEquity
us-gaap:StatementEquityComponents

us-gaap:AssetsCurrent

us-gaap:CashAndCashEquivalentsAtCarryingValue

us-gaap:AccountsReceivableNetCurrent

us-gaap:PrepaidExpenseAndOtherAssetsCurrent

us-gaap:PropertyPlantAndEquipmentNet

us-gaap:Goodwill
us-gaap:StatementBusinessSegments

us-gaap:IntangibleAssetsNetExcludingGoodwill

us-gaap:FiniteLivedIntangibleAssetsNet
us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:OtherAssetsNoncurrent

us-gaap:LiabilitiesCurrent

us-gaap:LongTermDebtCurrent

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent
us-gaap:LongtermDebtType
us-gaap:LongTermDebt

us-gaap:LongTermDebtNoncurrent

us-gaap:OtherLiabilitiesNoncurrent

us-gaap:StockholdersEquity
us-gaap:StatementEquityComponents

us-gaap:CommonStockValue

us-gaap:RetainedEarningsAccumulatedDeficit

us-gaap:TreasuryStockValue

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:NetCashProvidedByUsedInOperatingActivities

us-gaap:NetIncomeLoss
us-gaap:StatementEquityComponents
us-gaap:ConsolidationItems
us-gaap:DepreciationDepletionAndAmortization

us-gaap:NetCashProvidedByUsedInInvestingActivities

us-gaap:NetCashProvidedByUsedInFinancingActivities

us-gaap:ProceedsFromIssuanceOfLongTermDebt

us-gaap:RepaymentsOfLongTermDebt

us-gaap:PaymentsForRepurchaseOfCommonStock

us-gaap:RepaymentsOfLongTermDebt

us-gaap:EffectiveIncomeTaxRateContinuingOperations

us-gaap:ShareBasedCompensation

us-gaap:UnrecognizedTaxBenefits

us-gaap:OperatingLeaseRightOfUseAsset

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents

it:BusinessCombinationAcquisitionandIntegrationRelatedCosts
us-gaap:ConsolidationItems

it:InterestExpenseandOtherNonoperatingIncome

it:OperatingLeaseRightOfUseAssetReductionInCarryingAmount
us-gaap:ConsolidationItems, us-gaap:Range
it:SegmentReportingInformationPercentofTargetBonusChargesAllocatedtoSegments

it:TreasuryStockAveragePricePaidPerShare

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue
us-gaap:StatementEquityComponents

us-gaap:AllocatedShareBasedCompensationExpense
us-gaap:AwardType
us-gaap:IncomeStatementLocation

us-gaap:AmortizationOfFinancingCosts

us-gaap:AmortizationOfIntangibleAssets

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect

us-gaap:ContractWithCustomerLiabilityRevenueRecognized

us-gaap:DeferredIncomeTaxExpenseBenefit

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost

us-gaap:Depreciation

us-gaap:DepreciationAndAmortization

us-gaap:DerivativeGainLossOnDerivativeNet
us-gaap:IncomeStatementLocation

us-gaap:DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax

us-gaap:EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents

us-gaap:EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount

us-gaap:FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss
us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:GainLossOnSaleOfBusiness

us-gaap:GoodwillForeignCurrencyTranslationGainLoss
us-gaap:StatementBusinessSegments

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments

us-gaap:IncreaseDecreaseInAccountsPayableAndAccruedLiabilities

us-gaap:IncreaseDecreaseInAccountsReceivable

us-gaap:IncreaseDecreaseInDeferredCharges

us-gaap:IncreaseDecreaseInDeferredRevenue

us-gaap:IncreaseDecreaseInOtherOperatingAssets

us-gaap:IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements

us-gaap:OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax
us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax
us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:OtherComprehensiveIncomeLossNetOfTax
us-gaap:StatementEquityComponents

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax

us-gaap:PaymentsForCapitalImprovements

us-gaap:PaymentsToAcquireBusinessesNetOfCashAcquired

us-gaap:ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions

us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax
us-gaap:StatementEquityComponents
us-gaap:StatementBusinessSegments, us-gaap:SubsequentEventType
us-gaap:RestructuringAndRelatedCostNumberOfPositionsEliminatedPeriodPercent
us-gaap:SubsequentEventType

us-gaap:StockGrantedDuringPeriodValueSharebasedCompensation
us-gaap:StatementEquityComponents

us-gaap:StockRepurchasedDuringPeriodValue
us-gaap:StatementEquityComponents

us-gaap:TreasuryStockSharesAcquired

it:DebtLongtermandShorttermCombinedAmountGross

it:NumberofEnterprisesServed

us-gaap:AccountsReceivableGrossCurrent

us-gaap:AdditionalPaidInCapital

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent

us-gaap:AssetsFairValueDisclosure
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument

us-gaap:ContractWithCustomerAssetGross

us-gaap:ContractWithCustomerLiability

us-gaap:ContractWithCustomerLiabilityCurrent

us-gaap:ContractWithCustomerLiabilityNoncurrent
us-gaap:CreditFacility
us-gaap:DebtInstrumentCarryingAmount
us-gaap:DebtInstrument, us-gaap:LongtermDebtType
us-gaap:LongtermDebtType
us-gaap:LongtermDebtType
us-gaap:DebtInstrumentFaceAmount

us-gaap:DebtIssuanceCostsLineOfCreditArrangementsNet

us-gaap:DebtLongtermAndShorttermCombinedAmount

us-gaap:DerivativeAssetsLiabilitiesAtFairValueNet
us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:Range, us-gaap:DerivativeInstrumentRisk
us-gaap:DerivativeFixedInterestRate

us-gaap:DerivativeNotionalAmount
us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:DerivativeNumberOfInstrumentsHeld
us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation
us-gaap:DerivativeInstrumentRisk

us-gaap:FiniteLivedIntangibleAssetsAccumulatedAmortization
us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:FiniteLivedIntangibleAssetsGross
us-gaap:FiniteLivedIntangibleAssetsByMajorClass
us-gaap:DerivativeInstrumentRisk
us-gaap:InterestRateFairValueHedgeDerivativeAtFairValueNet

us-gaap:LiabilitiesFairValueDisclosure
us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument
us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument, us-gaap:LongtermDebtType

us-gaap:OperatingLeaseLiabilityNoncurrent

us-gaap:OtherDeferredCostsNet

us-gaap:PreferredStockSharesAuthorized
us-gaap:Range, us-gaap:SubsequentEventType
us-gaap:RestructuringAndRelatedCostExpectedCost1

us-gaap:RevenueRemainingPerformanceObligation

us-gaap:TreasuryStockShares

Tables

  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:CommonStockValue ████████████▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.0NANANA
us-gaap:CommonStockSharesIssued ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁█▁▁▁▁▁▁▁▁163163163163163163163163163163163163156156156156156156156156156156156156156156156156156234156156156156156156156156NANANA
us-gaap:CommonStockSharesAuthorized ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁█▁▁▁▁▁▁▁▁250250250250250250250250250250250250250250250250250250250250250250250250250250250250250000250250250250250250250250NANANA
us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding 90NA909191NA929291NA908984NA838383NA848487NA899093949595NA959596NA989999NA989899
us-gaap:WeightedAverageNumberOfSharesOutstandingBasic 89NA899089NA909191NA908982NA828282NA828386NA888991929393NA939393NA969696NA959595
us-gaap:EarningsPerShareBasic ▇▇▆█▅▇▅▆▄█▃▁▆▇▅▆▆▇▅▆▅▆▅▆▅▅▆▅▆▅▆▅▆▅▅▅▅▅▅▅0.840.760.461.150.230.93000000000000020.130.51-0.221.23-0.53-1.030.440.79999999999999980.370.580.490.78999999999999980.370.610.330.67000000000000020.380.590.410.410.50.390.63000000000000010.340.440.370.480.320.330.30.390.210.210.2
us-gaap:EarningsPerShareDiluted ▇▆▆█▅▇▅▆▄█▃▁▆▇▅▆▆▇▅▆▅▆▅▆▅▅▆▅▆▅▆▅▆▅▅▅▅▅▅▅0.830.740.461.130.230.91000000000000010.130.5-0.221.23-0.53-1.030.430.790.360.570.480.770.360.610.320.65999999999999970.380.580.40.40.490.380.60999999999999990.330.430.360.469999999999999860.310.320.290.360.20.20.19
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax ▇█▆▇▆▇▆▆▆▇▅▅▄▄▃▃▃▄▃▃▂▃▂▃▂▂▂▂▂▂▂▂▂▁▂▁▂▁▁▁1018120310001070970108892110019631014828843625703574609557643500547471583470519446410446406474374397369427345365329382296314295
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ProductOrService it:ResearchRevenue█▇▆▆▆▅▅▅▅▃▂▁909882840826825797774770763692653613NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementBusinessSegments it:ResearchSegment██▇▇▇▆▆▆▅▄▃▃▁909882840826825797774770763692653613511NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementBusinessSegments,us-gaap:TimingOfTransferOfGoodOrService it:ResearchSegment,us-gaap:TransferredOverTime██▇▇▇▆▆▆▆▄▄▃▁829807769754752731709708701638600570466NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementGeographical it:EuropeMiddleEastAfrica▆▇▇▇▇█▆▇█▇▇▅▁238254247253241264234242259247242212153NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementGeographical it:OtherInternational▇█▇▆▅▇▄▄▅▄▃▂▁130141128126118132107108110101929178NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementGeographical it:UnitedStatesAndCanada▅█▅▆▅▆▄▅▄▆▃▃▁650807624690611691579650593665493540392NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementGeographical,us-gaap:StatementBusinessSegments it:EuropeMiddleEastAfrica,it:ResearchSegment█▃▇▆▆▅▅▅▅▁▄▁205167196193193186180186184152176152NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementGeographical,us-gaap:StatementBusinessSegments it:OtherInternational,it:ResearchSegment█▇▇▇▇▆▅▅▄▁▂▁113109106103104102919089667068NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementGeographical,us-gaap:StatementBusinessSegments it:UnitedStatesAndCanada,it:ResearchSegment██▆▅▅▅▅▄▄▄▁▁590605538528527508502493489473406392NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:TimingOfTransferOfGoodOrService us-gaap:TransferredAtPointInTime▁█▃▆▂▇▂▄▂▆▂▃▁10831515323713828313319612924511616993NANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:TimingOfTransferOfGoodOrService us-gaap:TransferredOverTime██▇▇▇▆▆▆▇▅▄▄▁910887847833831805788804834769711673531NANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:Revenues ▇█▆▇▆▇▆▆▆▇▅▅▄▄▃▃▃▄▃▃▂▃▂▃▂▂▂▂▂▂▂▂▂▁▂▁▂▁▁▁1018120310001070970108892110019631014828843625703574609557643500547471583470519446410446406474374397369427345365329382296314295
 us-gaap:Revenues us-gaap:ConsolidationItems us-gaap:OperatingSegments▆█▆▇▆▇▅▆▆▆▄▅▂▃▂▂▂▃▁▂▁▂▁▁1018120310001070970108892110019631014828843625703574609557643500547471583470519NANANANANANANANANANANANANANANANA
 us-gaap:Revenues us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments us-gaap:OperatingSegments,it:ResearchSegment██▇▇▇▇▆▆▆▅▅▄▃▃▂▂▂▂▁▁▁▁▁▁909882840826825797774770763692653613504478461449440420396385381373365358NANANANANANANANANANANANANANANANA
us-gaap:CostOfGoodsAndServicesSold ▂█▃▄▂▅▁▃▂▅▁▂341450365387346407336367357398332352NANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:CostsAndExpenses ▆█▇▇▇▇▆▇▇▇▆▇▄▄▃▃▃▃▃▃▂▃▂▃▂▂▂▂▂▂▂▁▂▁▁▁▂▁▁▁8941067931954921959868915972951852942571594525526492542447462422488421438387351372352395324334315358298313283329263279266
us-gaap:SellingGeneralAndAdministrativeExpense ▇█▇▇▇▇▆▆▇▇▆▆▄▄▃▃▃▃▃▃▃▃▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁496557512514518488447460487465421408304289269272257258236237229235217218204181185180186164165162170148152141154127130130
 us-gaap:SellingGeneralAndAdministrativeExpense us-gaap:ConsolidationItems it:CorporateAndReconcilingItems▇█▇▇▇▆▆▆▆▆▅▅▂▂▂▂▁▁▁▁496557512514518488447460487465421408304289269272257258236237NANANANANANANANANANANANANANANANANANANANA
us-gaap:OperatingIncomeLoss ██▆▇▅█▅▇▄▆▃▁▆▇▅▆▆▇▅▆▅▇▅▆▆▆▆▆▆▅▆▆▆▅▅▅▆▅▅▅12413669116481295286-862-24-985310848836410152854895498159587354794962536947514553323429
 us-gaap:OperatingIncomeLoss us-gaap:ConsolidationItems us-gaap:OperatingSegments▃█▁676765636NA622673585NANANANANANANANANANANANANA48NA498159587354NANANANANANANANANANANANA
 us-gaap:OperatingIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments us-gaap:OperatingSegments,it:Consulting█▆▁292826NA282618NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:OperatingIncomeLoss us-gaap:ConsolidationItems,us-gaap:StatementBusinessSegments us-gaap:OperatingSegments,it:ResearchSegment█▅▁653621582NA575544534NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:InterestExpense ▅▆▅▅▅▆▅▇▇▇▇█▂▃▂▃▂▃▂▂▂▂▂▂▂▂▂▁▁▁▂▂▂▂▂▂▃▂▂▂262924242427263735393843585767653422222-2-3-22232227333
us-gaap:OtherNonoperatingIncomeExpense ▁▂█▂▂▁▂▃▂▃▃▂▂▄▃▃▃▃▆▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▃-10800-10101100311115000000000000000000001
us-gaap:OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax ▂▅▅▆▄▅▅▁▆▅█▅▅▄▅▅▅▅▄▅▄▄▄▅▅▅▅▅-46-4312-770-6020-44614-8-332-1-76-20-15-12004-1-3NA5-42NANANANANANANANA
us-gaap:IncomeTaxExpenseBenefit ▇█▆▅▆▇▇▇▄▁▅▃▆█▆▇▇▇▇▇▆▇▆▇▇▇▇▆▇▆▇▆▇▆▆▆▆▆▆▆214211-120262628-23-78-13-50123914292030212815331226181825151915191621131513109108
us-gaap:ComprehensiveIncomeNetOfTax ▄▇▅▇▄▆▅▄▅█▄▁▆▆▅▆▅▇▅▆▄▆▅▆▅▆▆▅▆▅▅▅▆▅▅▅▅▅▅-1571339106613-10111100-9338643049357016577392154374246335636363645213030362817NA
us-gaap:NetIncomeLoss ▇▇▆█▅▇▅▆▄█▃▁▆▇▅▆▆▇▅▆▅▆▅▆▆▆▆▆▆▅▆▅▆▅▅▅▆▅▅▅75674110320841146-19107-48-9236663047406530512859335337384636583141344530322936202019
 us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents us-gaap:RetainedEarnings▆▆▄█▃▇▃▅▁75674110320841146-19NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:Assets ▇█▇▇▇▇▆▇████▃▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁6800715167376729671462015944615269157283701169943365236722772304221121742091186117891904176817961757162816131567162114791380134913791304129512751285NANANA
us-gaap:Liabilities ▇█▇▇▇▇▆▇████▄▃▃▃▃▃▃▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁5910621258175765585753505003523159276299614861413262230622882357232423072251203119281743161615991520130612851248131412171165117811981110108010651098NANANA
us-gaap:LiabilitiesAndStockholdersEquity ▇█▇▇▇▇▆▇████▃▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁6800715167376729671462015944615269157283701169943365236722772304221121742091186117891904176817961757162816131567162114791380134913791304129512751285NANANA
us-gaap:StockholdersEquity ▇███▇▇████▇▇▃▂▂▂▁▁▁▁▁▃▃▃▃▄▄▄▄▄▃▃▃▃▃▃▃89093891996385685094192198798386385310260-10-52-112-132-159-170-139161152197236321328319306261214171181194215210187NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapital█▇▆▆▅▄▃▃▂▁1922189918851868185218231810179817881761NANANA863NANANA818NANANA764NANANANANANA679NANANA646NANANA611NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:CommonStock▄▄▄▄▄▄▄▄▄▄82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.0NANANA78000.0NANANA78000.0NANANA78000.0NANANANANANA78000.0NANANA78000.0NANANA78000.0NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:RetainedEarnings█▇▆▅▄▃▂▂▁▂2063198819211879177617551671165916131647NANANA1644NANANA1450NANANA1275NANANANANANA908NANANA742NANANA605NANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:AssetsCurrent ▅▆▅▅▅▅▄▅▇█▅▅▇▄▃▃▃▃▃▃▂▃▂▂▂▂▂▂▂▂▁▁▁▁▁▁▁1772201817061691171618111535160823102588181217592175134312451233117911401061106610001096959971945935923875927781686676705633625616621NANANA
us-gaap:CashAndCashEquivalentsAtCarryingValue ▂▂▂▂▁▁▂▁▂▄▄▄█▃▃▃▃▃▃▃▂▃▂▂▂▃▂▂▂▂▁▁▁▁▁▁▁▁▁▁2272803062181491562101411895386305891227474465445403372371357281365341317283374333269299255150138142156125109120148122105
us-gaap:AccountsReceivableNetCurrent ▇█▆▆▇▇▆▆▇▇▅▅▄▃▃▃▃▃▂▂▂▂▂▂▂▁▂▂▂▁▁▁▂▁▁▁▁114813261028111211781255979108311341176874886716643560613602580482527526552449493496392432441463370389384421349360345364NANANA
us-gaap:PrepaidExpenseAndOtherAssetsCurrent ▆▅▇▆▆▆▇█▇▄▆▅▃▂▄▁▁▁▄▂▃▁▃▂▂▃▂▂▂▃▂▂▁▂▂▃▁1561461731481561651781991751241641419184107635462114828863877167918081758978786366739264NANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:PropertyPlantAndEquipmentNet ██▇▇▆▆▆▅▅▅▅▅▃▃▃▃▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▂▁▁▁▁34634430029127126724622522322121619712612111811710810810910710497939594908988898077696857524547NANANA
us-gaap:Goodwill ▇▇▇▇▇▇▇▇▇███▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁292729372939293029062923291029742956298731453169855738742742718715723583579586593598589518516516519519515510508510516514510NANANA
 us-gaap:Goodwill us-gaap:StatementBusinessSegments it:ResearchSegment██████████▇▇▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁264226512655264526222638262526202601261923362482712595598602578575583441439445451455447376374375377376NANA366NANANA368NANANA
us-gaap:IntangibleAssetsNetExcludingGoodwill ▅▅▅▅▅▆▆▆▆▇██▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁8649259369731016104210851177124712921564159581768199909696272830333634781011131467781113NANANA
us-gaap:FiniteLivedIntangibleAssetsNet ▅▅▅▅▅▆▆▆▆▇██▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁864925936973101610421085117712471292156415958176819990969627283033363478101113146778713NANANA
 us-gaap:FiniteLivedIntangibleAssetsNet us-gaap:FiniteLivedIntangibleAssetsByMajorClass us-gaap:CustomerRelationships▅▆▆▆▆▆▆▇▇▇██▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁8098618668959299469791044108911071251126753464856515356151516171818234455334435NANANA
us-gaap:OtherAssetsNoncurrent ▆▆▅▆▄▄▄▄▅▅██▃▁▂▂▂▂▂▁▁▂▂▂▂▁▁▁▁▁▁▁▂▂▂▁▂2112222012051701561661661761932732721268788111115113100777592899493767676738486869095928793NANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:LiabilitiesCurrent ▆▇▆▆▆▆▆▆█▇▆▅▃▃▃▃▂▃▂▂▃▂▃▃▂▂▂▂▂▂▁▁▁▁▁▁▁2530285625272482256826202343251331852822248222431470146014171387129113231235120414201215135813451266104310149751070968908911921834799784811NANANA
us-gaap:LongTermDebtCurrent ▂▂▂▂▃▂▂▃█▄▅▃▁▁▁▁▁▁▁▁▃▁▃▃▃▁▁▁▂▂▁▂▁▁▁▂▁149139130121204165932847893794192772930407057352020285202452462226561579080701005052558240NANANA
us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent ▅█▆▆▅▇▆▅▅▇▅▅▃▄▃▃▂▄▃▂▂▃▂▂▂▂▂▁▃▂▁▁▂▁▁▁▂533788593564526710599542532666550517331440348287247387290262240353266251211224204180287206178160259183172143247NANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
 us-gaap:LongTermDebt us-gaap:LongtermDebtType us-gaap:SeniorNotes▄▄785785NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
us-gaap:LongTermDebtNoncurrent ▅▅▅▅▆▆▆▆▆▇▇█▄▂▂▂▃▃▃▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁2035204320512059209421162077214621862899292231401599664696756832790820695380385125128132140143147115120130140150157165172180NANANA
us-gaap:OtherLiabilitiesNoncurrent ▆▅▅▅▄▆▆▆▆▆██▂▂▂▂▂▂▂▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁530479462456424613582570555577743756192181174214200193196131128142132125121122126125129128126127126118115108107NANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:StockholdersEquity ▇███▇▇████▇▇▃▂▂▂▁▁▁▁▁▃▃▃▃▄▄▄▄▄▃▃▃▃▃▃▃89093891996385685094192198798386385310260-10-52-112-132-159-170-139161152197236321328319306261214171181194215210187NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:AdditionalPaidInCapital█▇▆▆▅▄▃▃▂▁1922189918851868185218231810179817881761NANANA863NANANA818NANANA764NANANANANANA679NANANA646NANANA611NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:CommonStock▄▄▄▄▄▄▄▄▄▄82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.0NANANA78000.0NANANA78000.0NANANA78000.0NANANANANANA78000.0NANANA78000.0NANANA78000.0NANANA
 us-gaap:StockholdersEquity us-gaap:StatementEquityComponents us-gaap:RetainedEarnings█▇▆▅▄▃▂▂▁▂2063198819211879177617551671165916131647NANANA1644NANANA1450NANANA1275NANANANANANA908NANANA742NANANA605NANANA
us-gaap:CommonStockValue ████████████▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.0NANANA
us-gaap:RetainedEarningsAccumulatedDeficit ██▇▇▇▇▆▆▆▆▅▆▆▆▆▅▅▅▅▅▄▄▄▄▄▃▃▃▂▂▂▂▂▁▁▁▁20631988192118791776175516711659161316471539158816801644157715381490145013841354130312751215118211291029991945908849818776742697667634605NANANA
us-gaap:TreasuryStockValue ███▇▇▇▆▆▆▆▆▆▆▆▆▆▆▆▆▆▅▄▄▄▃▂▂▂▂▂▂▂▂▁▁▁▁2927287128052711271026882517251224462426242424182410239623912391238723572301228421821857181617371634142213631318128712681268126412131146109410601045NANANA
us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax ▁▄▄▄▅▆▆▆█▇▇▅▅▅▅▅▅▅▅▆▅▆▇▇▇▇▇▇▇▇▇▇▇▇▇▇▇-168-77-81-73-61-39-22-24321-1-48-47-49-47-48-49-44-49-35-42-21-298622583855141614NANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInOperatingActivities ▃▄▇▇▃▃█▆▂▂▅▅▁▄▅▅▂▄▅▅▂▄▅▅▂55822192273545249174222149112-298312814887911614357112213616NANA197110980187911288-24796469-7
us-gaap:NetCashProvidedByUsedInInvestingActivities ▇▇▇▇▇▇▇█▇▇▇▁▇▇▇▇▇▇▇▇▇▇▇▇▇-24-62-36-39-22-5673383-16-35-46-2523-140-17-11-47-7-10-207-11-11-15-6-16-124NANA-9-13-10-23-7-18-14-5-3-9-4-4-15
us-gaap:NetCashProvidedByUsedInFinancingActivities ▃▃▃▂▃▃▂▁▂▃▃█▆▃▃▃▃▃▃▃▃▃▃▃▃-68-53-90-118-23-43-266-618-329-65-801768917-43-97-6026-66115-62-54-12-78-85-32NANA-36-140-41-17-75-61-6717-98-45-4314
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInOperatingActivities ▃▄▇▇▃▃█▆▂▂▅▅▁▄▅▅▂▄▅▅▂▄▅▅▂55822192273545249174222149112-298312814887911614357112213616NANA197110980187911288-24796469-7
us-gaap:NetIncomeLoss ▇▇▆█▅▇▅▆▄█▃▁▆▇▅▆▆▇▅▆▅▆▅▆▆▆▆▆▆▅▆▅▆▅▅▅▆▅▅▅75674110320841146-19107-48-9236663047406530512859335337384636583141344530322936202019
 us-gaap:NetIncomeLoss us-gaap:StatementEquityComponents us-gaap:RetainedEarnings▆▆▄█▃▇▃▅▁75674110320841146-19NANANANANANANANANANANANANANANANANANANANANANANANANANANANANANANA
 us-gaap:DepreciationDepletionAndAmortization us-gaap:ConsolidationItems it:CorporateAndReconcilingItems▅▅▅▅▅▅▇▆▇▇▇█▂▁▁▁▁▁▁▁5453525253526866687168831615151515151110NANANANANANANANANANANANANANANANANANANANA
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInInvestingActivities ▇▇▇▇▇▇▇█▇▇▇▁▇▇▇▇▇▇▇▇▇▇▇▇▇-24-62-36-39-22-5673383-16-35-46-2523-140-17-11-47-7-10-207-11-11-15-6-16-124NANA-9-13-10-23-7-18-14-5-3-9-4-4-15
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:NetCashProvidedByUsedInFinancingActivities ▃▃▃▂▃▃▂▁▂▃▃█▆▃▃▃▃▃▃▃▃▃▃▃▃-68-53-90-118-23-43-266-618-329-65-801768917-43-97-6026-66115-62-54-12-78-85-32NANA-36-140-41-17-75-61-6717-98-45-4314
us-gaap:ProceedsFromIssuanceOfLongTermDebt ▁▁▁▁▁▁▁▁▁▁▂█▅▁▁▄▂▁▂▁▂▂▁▁▂000-3035000001401930955-32-8276070-1013055265225-123151NANA200127-3247NA-5-3040173-361152
us-gaap:RepaymentsOfLongTermDebt ▂▂▂▃▂▁▄▆▄▂▃▃▂▂▂█▂▂▂▂▂▃▂▂▂0009018-10926155330464219101187781555555190331NANA20077775555252212114
us-gaap:PaymentsForRepurchaseOfCommonStock ▃▂▃▁▂▄▁▂▂▁▁▁▁▁▁▁▂▂▁▄█▂▃▃▅735794144156867284311216064556111173244479111195NANA48224777705335512313935
  2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
us-gaap:RepaymentsOfLongTermDebt ▂▂▂▃▂▁▄▆▄▂▃▃▂▂▂█▂▂▂▂▂▃▂▂▂0009018-10926155330464219101187781555555190331NANA20077775555252212114

Common Stock Value

us-gaap:CommonStockValue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.0
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Common Stock Par Or Stated Value Per Share

Shares Outstanding

Common Stock Shares Issued

us-gaap:CommonStockSharesIssued



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value163163163163163163163163163163163163156156156156156156156156156156156156156156156156156156234156156156156156156156156156
Percentage of CommonStockSharesIssued100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Common Stock Shares Authorized

us-gaap:CommonStockSharesAuthorized



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value250250250250250250250250250250250250250250250250250250250250250250250250250250250250250250000250250250250250250250250250
Percentage of CommonStockSharesAuthorized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Diluted Shares Outstanding

us-gaap:WeightedAverageNumberOfDilutedSharesOutstanding



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value90909191929291908984838383848487899093949595959596989999989899
Percentage of WeightedAverageNumberOfDilutedSharesOutstanding100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Weighted Average Number Of Shares Outstanding Basic

us-gaap:WeightedAverageNumberOfSharesOutstandingBasic



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-302010-03-31
Value89899089909191908982828282828386888991929393939393969696959595
Percentage of WeightedAverageNumberOfSharesOutstandingBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Basic

us-gaap:EarningsPerShareBasic



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.840.760.461.150.230.93000000000000020.130.51-0.221.23-0.53-1.030.440.79999999999999980.370.580.490.78999999999999980.370.610.330.67000000000000020.380.590.410.410.50.390.63000000000000010.340.440.370.480.320.330.30.390.210.210.2
Percentage of EarningsPerShareBasic100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Earnings Per Share Diluted

us-gaap:EarningsPerShareDiluted



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0.830.740.461.130.230.91000000000000010.130.5-0.221.23-0.53-1.030.430.790.360.570.480.770.360.610.320.65999999999999970.380.580.40.40.490.380.60999999999999990.330.430.360.469999999999999860.310.320.290.360.20.20.19
Percentage of EarningsPerShareDiluted100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Income Loss From Continuing Operations Per Basic Share

Income Loss From Continuing Operations Per Diluted Share

Revenue From Contract With Customer Excluding Assessed Tax

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1018120310001070970108892110019631014828843625703574609557643500547471583470519446410446406474374397369427345365329382296314295
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ProductOrService

it:Conferences



Period End2020-03-312019-03-31
Value1351
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:Conferences100.0100.0

it:Consulting



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value95103931039395789682857291
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax9.48.69.39.79.68.88.59.68.68.48.710.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax9.48.69.39.79.68.88.59.68.68.48.710.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:Consulting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:ResearchRevenue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value909882840826825797774770763692653613
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.273.384.177.185.173.284.076.979.368.378.972.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.273.384.177.185.173.284.076.979.368.378.972.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:ResearchRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementBusinessSegments

it:Conferences



Period End2020-03-312019-03-31
Value1351
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:Conferences100.0100.0

it:Consulting



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value9510393103939578968285729178
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax9.48.69.39.79.68.88.59.68.68.48.710.912.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax9.48.69.39.79.68.88.59.68.68.48.710.912.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:Consulting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:ResearchSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value909882840826825797774770763692653613511
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.273.384.177.185.173.284.076.979.368.378.972.781.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.273.384.177.185.173.284.076.979.368.378.972.781.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:ResearchSegment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementBusinessSegments, us-gaap:TimingOfTransferOfGoodOrService

it:Conferences, us-gaap:TransferredAtPointInTime



Period End2020-03-312019-03-31
Value1351
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:Conferences us-gaap:TransferredAtPointInTime100.0100.0

it:Consulting, us-gaap:TransferredAtPointInTime



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value14231524142281981372313
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.42.01.62.31.52.01.01.90.91.30.92.82.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.42.01.62.31.52.01.01.90.91.30.92.82.2
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:Consulting us-gaap:TransferredAtPointInTime100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:Consulting, us-gaap:TransferredOverTime



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value81807779787369777471646864
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax8.06.77.87.48.16.87.67.77.77.17.88.110.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax8.06.77.87.48.16.87.67.77.77.17.88.110.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:Consulting us-gaap:TransferredOverTime100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:ResearchSegment, us-gaap:TransferredAtPointInTime



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value80747171726564616254534344
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax7.96.27.16.77.56.07.06.16.55.46.45.27.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax7.96.27.16.77.56.07.06.16.55.46.45.27.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:ResearchSegment us-gaap:TransferredAtPointInTime100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:ResearchSegment, us-gaap:TransferredOverTime



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value829807769754752731709708701638600570466
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax81.467.176.970.477.667.277.070.872.862.972.567.674.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax81.467.176.970.477.667.277.070.872.862.972.567.674.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:ResearchSegment us-gaap:TransferredOverTime100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementGeographical

it:EuropeMiddleEastAfrica



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value238254247253241264234242259247242212153
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax23.421.124.723.724.824.325.424.226.924.429.325.224.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax23.421.124.723.724.824.325.424.226.924.429.325.224.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:EuropeMiddleEastAfrica100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:OtherInternational



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value130141128126118132107108110101929178
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax12.811.712.811.812.212.211.710.911.510.011.210.812.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax12.811.712.811.812.212.211.710.911.510.011.210.812.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:OtherInternational100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:UnitedStatesAndCanada



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value650807624690611691579650593665493540392
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax63.867.162.564.563.063.562.964.961.665.659.664.062.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax63.867.162.564.563.063.562.964.961.665.659.664.062.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:UnitedStatesAndCanada100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementGeographical, us-gaap:StatementBusinessSegments

it:EuropeMiddleEastAfrica, it:Conferences



Period End2020-03-312019-03-31
Value217
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.21.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.21.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:EuropeMiddleEastAfrica it:Conferences100.0100.0

it:EuropeMiddleEastAfrica, it:Consulting



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value303126332929263329292929
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax3.02.62.63.23.12.72.83.43.12.93.53.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax3.02.62.63.23.12.72.83.43.12.93.53.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:EuropeMiddleEastAfrica it:Consulting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:EuropeMiddleEastAfrica, it:ResearchSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value205167196193193186180186184152176152
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax20.213.919.618.120.017.119.518.619.215.121.318.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax20.213.919.618.120.017.119.518.619.215.121.318.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:EuropeMiddleEastAfrica it:ResearchSegment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:OtherInternational, it:Conferences



Period End2020-03-312019-03-31
Value55
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.60.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.60.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:OtherInternational it:Conferences100.0100.0

it:OtherInternational, it:Consulting



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value1178887677767
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.10.60.80.80.80.60.70.70.80.70.80.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.10.60.80.80.80.60.70.70.80.70.80.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:OtherInternational it:Consulting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:OtherInternational, it:ResearchSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value113109106103104102919089667068
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax11.19.110.79.710.79.49.99.09.36.58.58.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax11.19.110.79.710.79.49.99.09.36.58.58.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:OtherInternational it:ResearchSegment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:UnitedStatesAndCanada, it:Conferences



Period End2020-03-312019-03-31
Value529
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.63.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax0.63.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:UnitedStatesAndCanada it:Conferences100.0100.0

it:UnitedStatesAndCanada, it:Consulting



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value546458615559455545483654
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax5.35.45.95.75.75.45.05.64.74.84.46.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax5.35.45.95.75.75.45.05.64.74.84.46.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:UnitedStatesAndCanada it:Consulting100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:UnitedStatesAndCanada, it:ResearchSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value590605538528527508502493489473406392
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax57.950.353.849.354.346.754.549.350.846.749.146.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax57.950.353.849.354.346.754.549.350.846.749.146.6
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:UnitedStatesAndCanada it:ResearchSegment100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:TimingOfTransferOfGoodOrService

us-gaap:TransferredAtPointInTime



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value10831515323713828313319612924511616993
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax10.626.315.322.214.326.014.519.613.424.214.020.115.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax10.626.315.322.214.326.014.519.613.424.214.020.115.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:TransferredAtPointInTime100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:TransferredOverTime



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value910887847833831805788804834769711673531
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.473.784.777.885.774.085.580.486.675.886.079.985.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.473.784.777.885.774.085.580.486.675.886.079.985.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:TransferredOverTime100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Revenues

us-gaap:Revenues



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value1018120310001070970108892110019631014828843625703574609557643500547471583470519446410446406474374397369427345365329382296314295
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ConsolidationItems

us-gaap:OperatingSegments



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-30
Value1018120310001070970108892110019631014828843625703574609557643500547471583470519
Percentage of Revenues100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, it:Conferences



Period End2020-03-312019-03-31
Value1351
Percentage of Revenues1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax1.45.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments it:Conferences0.00.0

us-gaap:OperatingSegments, it:Consulting



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-30
Value95103931039395789682857291858879948487748876888293
Percentage of Revenues9.48.69.39.79.68.88.59.68.68.48.710.913.612.513.815.415.213.714.916.116.315.117.518.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax9.48.69.39.79.68.88.59.68.68.48.710.913.612.513.815.415.213.714.916.116.315.117.518.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments it:Consulting0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OperatingSegments, it:ResearchSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-30
Value909882840826825797774770763692653613504478461449440420396385381373365358
Percentage of Revenues89.273.384.177.185.173.284.076.979.368.378.972.780.768.180.473.679.065.379.270.480.963.977.669.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax89.273.384.177.185.173.284.076.979.368.378.972.780.768.180.473.679.065.379.270.480.963.977.669.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments it:ResearchSegment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Sales Revenue Net

Cost Of Goods And Services Sold

us-gaap:CostOfGoodsAndServicesSold



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value341450365387346407336367357398332352
Percentage of CostOfGoodsAndServicesSold100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax33.537.536.536.235.737.536.536.737.139.340.141.7

us-gaap:ConsolidationItems

it:CorporateAndReconcilingItems



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value01214-1-70118-337
Percentage of CostOfGoodsAndServicesSold-0.22.90.31.1-0.3-1.8-0.13.12.4-0.81.12.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.11.10.10.4-0.1-0.7-0.01.10.9-0.30.50.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:CorporateAndReconcilingItems0.00.00.00.00.00.00.00.00.00.00.00.0

Cost Of Services

Gross Profit

Operating Expenses

Costs And Expenses

us-gaap:CostsAndExpenses



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value8941067931954921959868915972951852942571594525526492542447462422488421438387351372352395324334315358298313283329263279266
Percentage of CostsAndExpenses100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax87.888.793.189.295.088.194.391.4100.993.8102.9111.791.484.591.586.388.484.289.584.489.783.689.584.386.885.783.486.783.286.784.285.583.886.385.986.186.188.989.190.1

Selling General And Administrative Expense

us-gaap:SellingGeneralAndAdministrativeExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value496557512514518488447460487465421408304289269272257258236237229235217218204181185180186164165162170148152141154127130130
Percentage of SellingGeneralAndAdministrativeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax48.746.351.248.153.544.848.646.050.645.950.948.448.741.247.044.646.240.247.343.448.740.446.142.045.844.241.644.439.244.041.644.039.942.941.843.040.543.141.544.1

us-gaap:ConsolidationItems

it:CorporateAndReconcilingItems



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-30
Value496557512514518488447460487465421408304289269272257258236237
Percentage of SellingGeneralAndAdministrativeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax48.746.351.248.153.544.848.646.050.645.950.948.448.741.247.044.646.240.247.343.4
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:CorporateAndReconcilingItems0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Operating Income Loss

us-gaap:OperatingIncomeLoss



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value12413669116481295286-862-24-985310848836410152854895498159587354794962536947514553323429
Percentage of OperatingIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax12.211.36.910.85.011.95.78.6-0.96.2-2.9-11.78.615.58.513.711.615.810.515.610.316.410.515.713.214.316.613.316.813.315.814.516.213.714.113.913.911.110.99.9

us-gaap:ConsolidationItems

it:CorporateAndReconcilingItems



Period End2020-03-312019-12-312019-09-302019-03-312018-12-312018-09-30
Value-552-629-567-573-544-532
Percentage of OperatingIncomeLoss-442.7-462.3-820.5-1176.2-419.8-1010.1
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-54.2-52.3-56.7-59.1-50.0-57.8
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax it:CorporateAndReconcilingItems0.00.00.00.00.00.0

us-gaap:OperatingSegments



Period End2020-03-312019-12-312019-09-302019-03-312018-12-312018-09-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-31
Value67676563662267358548498159587354
Percentage of OperatingIncomeLoss542.7562.3920.51276.2519.81110.1100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax66.463.663.664.261.963.510.310.515.713.214.316.613.3
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments0.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments

us-gaap:OperatingSegments, it:Conferences



Period End2020-03-312019-03-31
Value-618
Percentage of OperatingIncomeLoss-4.938.7
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.61.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments it:Conferences0.00.0

us-gaap:OperatingSegments, it:Consulting



Period End2020-03-312019-12-312019-09-302019-03-312018-12-312018-09-30
Value292826282618
Percentage of OperatingIncomeLoss23.621.338.458.820.334.9
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.92.42.73.02.42.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments it:Consulting0.00.00.00.00.00.0

us-gaap:OperatingSegments, it:ResearchSegment



Period End2020-03-312019-12-312019-09-302019-03-312018-12-312018-09-30
Value653621582575544534
Percentage of OperatingIncomeLoss524.0456.7842.41178.6420.41014.5
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax64.151.758.259.350.058.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:OperatingSegments it:ResearchSegment0.00.00.00.00.00.0

Interest Expense

us-gaap:InterestExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value262924242427263735393843585767653422222-2-3-22232227333
Percentage of InterestExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.62.42.42.32.62.52.93.83.63.94.75.20.91.21.01.21.11.21.21.00.70.80.60.50.50.50.5-0.6-0.7-0.60.50.60.80.70.80.81.91.01.01.1

Other Nonoperating Income Expense

us-gaap:OtherNonoperatingIncomeExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-10800-10101100311115000000000000000000001
Percentage of OtherNonoperatingIncomeExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-0.10.00.8-0.0-0.1-0.1-0.10.10.10.20.1-0.00.10.50.30.20.30.21.1-0.1-0.2-0.0-0.10.0-0.10.0-0.10.10.1-0.2-0.0-0.3-0.1-0.2-0.2-0.1-0.1-0.1-0.20.6

Other Comprehensive Income Loss Foreign Currency Transaction And Translation Adjustment Net Of Tax

us-gaap:OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value-46-4312-770-6020-44614-8-332-1-76-20-15-12004-1-35-42
Percentage of OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-4.6-0.40.41.2-0.70.70.1-6.02.1-0.45.60.10.7-1.2-0.50.50.4-0.2-1.61.1-4.3-2.6-2.70.2-0.11.0-0.3-0.91.4-1.10.7

Income Loss From Continuing Operations

Income Loss From Continuing Operations Before Income Taxes Domestic

Income Loss From Continuing Operations Before Income Taxes Foreign

Income Tax Expense Benefit

us-gaap:IncomeTaxExpenseBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value214211-120262628-23-78-13-50123914292030212815331226181825151915191621131513109108
Percentage of IncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax2.13.61.2-1.20.02.52.82.9-2.4-7.8-1.7-6.01.95.72.54.83.64.84.35.23.45.72.75.04.24.55.63.74.04.14.84.45.14.04.44.12.63.13.32.8

Income Taxes Paid Net

Comprehensive Income Net Of Tax

us-gaap:ComprehensiveIncomeNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value-1571339106613-10111100-9338643049357016577392154374246335636363645213030362817
Percentage of ComprehensiveIncomeNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-1.65.93.48.5-0.16.11.4-1.01.210.8-0.1-11.16.19.25.38.16.311.03.310.61.56.84.610.58.510.410.38.211.89.79.210.010.56.38.39.49.69.55.5

Net Income Loss

us-gaap:NetIncomeLoss



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value75674110320841146-19107-48-9236663047406530512859335337384636583141344530322936202019
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax7.45.64.19.72.17.71.34.6-2.010.6-5.8-10.95.89.55.37.97.210.26.19.36.010.17.210.28.49.310.49.012.48.410.49.310.58.88.88.99.66.86.46.6

us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value75674110320841146-19
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax7.45.64.19.72.17.71.34.6-2.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.0

Assets

us-gaap:Assets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value680071516737672967146201594461526915728370116994336523672277230422112174209118611789190417681796175717831628161315671621147913801349137913041295127512851215
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Liabilities

us-gaap:Liabilities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value591062125817576558575350500352315927629961486141326223062288235723242307225120311928174316161599152014221306128512481314121711651178119811101080106510981102
Percentage of Liabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets86.986.986.385.787.286.384.285.085.786.587.787.896.997.4100.5102.3105.1106.1107.6109.1107.891.591.489.086.579.780.279.679.681.182.384.487.386.885.183.383.585.590.7

Liabilities And Stockholders Equity

us-gaap:LiabilitiesAndStockholdersEquity



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value680071516737672967146201594461526915728370116994336523672277230422112174209118611789190417681796175717831628161315671621147913801349137913041295127512851215
Percentage of LiabilitiesAndStockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Stockholders Equity

us-gaap:StockholdersEquity



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-312007-12-31
Value89093891996385685094192198798386385310260-10-52-112-132-159-170-139161152197236361321328319306261214171181194215210187112-2117
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets13.113.113.714.312.813.715.815.014.313.512.312.23.12.6-0.5-2.3-5.1-6.1-7.6-9.1-7.88.58.611.013.520.319.820.420.418.917.715.612.713.214.916.716.514.59.30.00.0

us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-31
Value-8-8-5-5-5-5-5-5-5-5-5-5-5-5-4-4-4-4-5-5-5-6
Percentage of StockholdersEquity-1.0-0.9-0.6-0.6-0.7-0.7-0.6-0.6-0.6-0.6-0.7-0.7-5.6-9.545.09.04.33.63.73.54.3-3.7
Percentage of Assets-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.2-0.2-0.2-0.2-0.2-0.2-0.3-0.3-0.3-0.3
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedGainLossNetCashFlowHedgeParent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-31
Value-91-47-58-46-22-71616122-4-6-3-1
Percentage of StockholdersEquity-10.3-5.0-6.3-4.9-2.6-0.91.81.81.30.3-0.6-0.7-3.9-2.3
Percentage of Assets-1.4-0.7-0.9-0.7-0.3-0.10.30.30.20.0-0.1-0.1-0.1-0.1
Percentage of Assets us-gaap:AccumulatedGainLossNetCashFlowHedgeParent0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-168-77-81-73-61-39-22-24321-1-48-47-49-47-48-49-44-49-35-42-218551411-123
Percentage of StockholdersEquity-19.0-8.3-8.8-7.6-7.2-4.7-2.4-2.63.30.2-0.1-5.7-46.5-81.6455.290.943.933.530.920.930.3-13.12.31.93.27.810.18.2135.1
Percentage of Assets-2.5-1.1-1.2-1.1-0.9-0.6-0.4-0.40.50.0-0.0-0.7-1.4-2.1-2.1-2.1-2.2-2.0-2.4-1.9-2.4-1.10.50.40.41.10.90.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedTranslationAdjustment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-31
Value-68-22-17-20-33-26-33-342549-37-38-42-34-31-34-36-35-27-33-13
Percentage of StockholdersEquity-7.7-2.4-1.9-2.2-3.9-3.1-3.6-3.82.60.51.1-4.3-37.1-69.8325.058.830.627.622.016.024.0-8.3
Percentage of Assets-1.0-0.3-0.3-0.3-0.5-0.4-0.6-0.60.40.10.1-0.5-1.1-1.8-1.5-1.3-1.6-1.7-1.7-1.5-1.9-0.7
Percentage of Assets us-gaap:AccumulatedTranslationAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value1922189918851868185218231810179817881761863818764718679646611590570545
Percentage of StockholdersEquity216.0202.4205.0193.9216.2214.4192.3195.1181.1179.11417.8-618.2474.3198.9221.7355.8327.1525.0-2677.23116.2
Percentage of Assets28.326.628.027.827.629.430.529.225.924.236.537.640.140.341.946.947.648.60.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.0
Percentage of StockholdersEquity0.00.00.00.00.00.00.00.00.00.00.1-0.10.00.00.00.00.00.1-0.40.4
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value20631988192118791776175516711659161316471644145012751091908742605509426322
Percentage of StockholdersEquity231.8211.9208.9195.0207.3206.3177.5180.1163.4167.52700.5-1095.7791.1302.0296.2408.5323.8452.7-2000.51843.4
Percentage of Assets30.327.828.527.926.528.328.127.023.322.669.466.767.061.256.053.847.141.90.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-2927-2871-2805-2711-2710-2688-2517-2512-2446-2426-2396-2357-1857-1457-1287-1213-1045-999-1016-874
Percentage of StockholdersEquity-328.8-305.9-305.1-281.3-316.3-316.0-267.4-272.7-247.8-246.8-3936.81780.4-1152.3-403.3-419.9-667.5-558.7-887.84769.9-4995.1
Percentage of Assets-43.0-40.2-41.6-40.3-40.4-43.4-42.4-40.8-35.4-33.3-101.2-108.4-97.5-81.7-79.4-87.9-81.3-82.20.00.0
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Assets Current

us-gaap:AssetsCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value17722018170616911716181115351608231025881812175921751343124512331179114010611066100010969599719451084935923875927781686676705633625616621557
Percentage of AssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets26.128.225.325.125.629.225.826.133.435.525.825.264.756.754.753.553.352.550.757.355.957.654.254.153.860.857.457.255.857.252.949.750.151.148.648.348.348.345.9

Cash And Cash Equivalents At Carrying Value

us-gaap:CashAndCashEquivalentsAtCarryingValue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-312009-12-312008-12-312007-12-31
Value2272803062181491562101411895386305891227474465445403372371357281365341317283423374333269299255150138142156125109120148122105116140109
Percentage of CashAndCashEquivalentsAtCarryingValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.43.94.63.22.22.53.52.32.77.49.08.436.520.020.419.318.317.217.719.215.719.219.317.716.123.823.020.717.218.517.310.910.310.312.09.78.59.30.00.00.09.60.00.0

Accounts Receivable Net Current

us-gaap:AccountsReceivableNetCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value114813261028111211781255979108311341176874886716643560613602580482527526552449493496490392432441463370389384421349360345364317
Percentage of AccountsReceivableNetCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets16.918.515.316.517.620.216.517.616.416.212.512.721.327.224.626.627.326.723.128.429.429.025.427.428.327.524.126.828.228.625.128.228.530.526.827.827.128.426.1

Prepaid Expense And Other Assets Current

us-gaap:PrepaidExpenseAndOtherAssetsCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value156146173148156165178199175124164141918410763546211482886387716763918081758978786366739264
Percentage of PrepaidExpenseAndOtherAssetsCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.32.02.62.22.32.73.03.22.51.72.42.02.73.64.72.82.52.95.54.44.93.44.94.03.93.65.65.05.24.76.15.75.84.65.15.77.25.0

Noncurrent Assets

Property Plant And Equipment Gross

Accumulated Depreciation Depletion And Amortization Property Plant And Equipment

Property Plant And Equipment Net

us-gaap:PropertyPlantAndEquipmentNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value346344300291271267246225223221216197126121118117108108109107104979395949190898889807769685752454752
Percentage of PropertyPlantAndEquipmentNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets5.14.84.54.34.04.34.13.73.23.03.12.83.85.15.25.14.95.05.25.85.85.15.35.35.45.15.55.55.65.55.45.65.24.94.44.13.63.74.3

Goodwill

us-gaap:Goodwill



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-04-052017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value2927293729392930290629232910297429562987314531692427855738742742718715723583579586593598589519518516516519519515510508510516514510513
Percentage of Goodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets43.141.143.643.543.347.149.048.342.841.044.945.30.025.431.232.632.232.532.934.631.332.430.833.533.333.629.131.832.033.032.035.137.337.936.939.139.840.439.742.3

us-gaap:StatementBusinessSegments

it:Conferences



Period End2020-03-312019-12-312018-12-312017-12-312016-12-31
Value18818918718746
Percentage of Goodwill6.46.56.46.36.3
Percentage of Assets2.82.73.02.62.0
Percentage of Assets it:Conferences0.00.00.00.00.0

it:Consulting



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-312010-12-31
Value9697969797979797989797969696979897989899989910010110010010099991009999
Percentage of Goodwill3.33.33.33.33.33.33.33.33.33.33.13.111.313.113.113.313.613.813.717.017.016.916.916.917.119.419.319.319.319.319.619.6
Percentage of Assets1.41.41.41.41.41.61.61.61.41.31.41.42.94.14.34.34.44.54.75.35.55.25.75.65.75.66.26.26.36.27.27.8
Percentage of Assets it:Consulting0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

it:ResearchSegment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302011-12-312010-12-31
Value264226512655264526222638262526202601261923362482712595598602578575583441439445451455447376376374375377376366368
Percentage of Goodwill90.390.290.390.390.290.390.288.188.087.774.378.383.280.680.681.180.580.480.675.875.875.976.076.175.872.572.672.572.672.672.672.272.2
Percentage of Assets38.937.139.439.339.042.544.242.637.636.033.335.521.225.226.326.126.226.527.923.724.623.425.525.425.421.123.123.223.923.325.526.628.7
Percentage of Assets it:ResearchSegment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Intangible Assets Net Excluding Goodwill

us-gaap:IntangibleAssetsNetExcludingGoodwill



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value8649259369731016104210851177124712921564159581768199909696272830333634678101113146778111324
Percentage of IntangibleAssetsNetExcludingGoodwill100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets12.712.913.914.515.116.818.319.118.017.722.322.82.43.23.64.34.14.44.61.51.61.61.92.02.00.30.50.50.70.70.91.00.50.50.60.70.91.12.0

Finite Lived Intangible Assets Net

us-gaap:FiniteLivedIntangibleAssetsNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value8649259369731016104210851177124712921564159581768199909696272830333634678101113146778713
Percentage of FiniteLivedIntangibleAssetsNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets12.712.913.914.515.116.818.319.118.017.722.322.82.43.23.64.34.14.44.61.51.61.61.92.02.00.30.50.50.70.70.91.00.50.50.60.70.61.1

us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:ComputerSoftwareIntangibleAsset



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-30
Value434954606671778491971731736781011126333451111111
Percentage of FiniteLivedIntangibleAssetsNet5.05.35.96.26.56.97.27.17.37.511.110.98.49.310.410.712.413.06.713.212.012.914.215.34.716.715.815.515.014.514.2
Percentage of Assets0.60.70.80.91.01.21.31.41.31.32.52.50.20.30.40.50.50.60.30.20.20.20.30.30.10.10.10.10.10.10.1
Percentage of Assets us-gaap:ComputerSoftwareIntangibleAsset0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CustomerRelationships



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value80986186689592994697910441089110712511267534648565153561515161718181234455334435
Percentage of FiniteLivedIntangibleAssetsNet93.793.292.692.091.590.890.288.787.385.780.079.565.460.759.556.856.855.858.556.056.254.953.151.353.729.033.235.138.339.540.742.049.951.152.052.851.140.0
Percentage of Assets11.912.112.913.313.815.316.517.015.815.217.818.11.62.02.12.42.32.52.70.80.90.91.01.01.10.10.20.20.30.30.40.40.20.30.30.30.30.4
Percentage of Assets us-gaap:CustomerRelationships0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:MediaContent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value1224567244056112124111511130111112222233
Percentage of FiniteLivedIntangibleAssetsNet0.20.30.30.40.50.60.72.13.24.47.27.81.52.21.65.41.62.013.63.03.74.34.75.35.534.530.728.526.025.023.722.8
Percentage of Assets0.00.00.00.10.10.10.10.40.60.81.61.80.00.10.10.20.10.10.60.00.10.10.10.10.10.10.10.20.20.20.20.2
Percentage of Assets us-gaap:MediaContent0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:OtherIntangibleAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-31
Value91011131417212426302721
Percentage of FiniteLivedIntangibleAssetsNet1.11.21.31.41.51.71.92.12.22.41.727.8
Percentage of Assets0.10.20.20.20.20.30.40.40.40.40.40.9
Percentage of Assets us-gaap:OtherIntangibleAssets0.00.00.00.00.00.00.00.00.00.00.00.0

Deferred Tax Assets Liabilities Net

Other Assets Noncurrent

us-gaap:OtherAssetsNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value21122220120517015616616617619327327212687881111151131007775928994938176767673848686909592879367
Percentage of OtherAssetsNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets3.13.13.03.12.52.52.82.72.62.73.93.93.83.73.94.85.25.24.84.24.24.85.15.25.34.64.74.74.94.55.76.36.46.57.37.26.97.25.5

Liabilities Current

us-gaap:LiabilitiesCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value25302856252724822568262023432513318528222482224314701460141713871291132312351204142012151358134512661159104310149751070968908911921834799784811898
Percentage of LiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets37.239.937.536.938.342.339.440.946.138.835.432.143.761.762.260.258.460.959.164.779.463.876.874.972.165.064.162.962.266.065.565.867.566.864.061.761.563.173.9

Debt Current

Long Term Debt Current

us-gaap:LongTermDebtCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value14913913012120416593284789379419277293040705735202028520245246222686561579080701005052558240205
Percentage of LongTermDebtCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets2.22.01.91.83.12.71.64.611.45.26.04.00.91.31.83.02.61.61.01.115.91.113.913.712.73.94.03.83.75.65.45.17.43.64.04.26.53.116.9

Accounts Payable Current

Accounts Payable And Accrued Liabilities Current

us-gaap:AccountsPayableAndAccruedLiabilitiesCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value533788593564526710599542532666550517331440348287247387290262240353266251211325224204180287206178160259183172143247255
Percentage of AccountsPayableAndAccruedLiabilitiesCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets7.911.08.88.47.811.510.18.87.79.27.87.49.918.615.312.511.217.813.914.113.418.615.114.012.018.213.812.711.517.713.912.911.918.814.113.311.319.321.1

Other Accrued Liabilities Current

Taxes Payable Current

Other Liabilities Current

Long Term Debt

us-gaap:LongtermDebtType

us-gaap:LongTermDebt

us-gaap:SeniorNotes



Period End2020-03-312019-12-31
Value785785
Percentage of LongTermDebt100.0100.0
Percentage of Assets11.611.0
Percentage of Assets us-gaap:SeniorNotes0.00.0

Long Term Debt Noncurrent

us-gaap:LongTermDebtNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value2035204320512059209421162077214621862899292231401599664696756832790820695380385125128132136140143147115120130140150157165172180124
Percentage of LongTermDebtNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets29.928.630.430.631.234.134.934.931.639.841.744.947.528.130.632.837.636.339.237.321.220.27.17.27.57.68.68.99.47.18.19.410.410.912.112.713.514.010.2

Deferred Tax Liabilities Noncurrent

Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent

Other Liabilities Noncurrent

us-gaap:OtherLiabilitiesNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value53047946245642461358257055557774375619218117421420019319613112814213212512112612212612512912812612712611811510810780
Percentage of OtherLiabilitiesNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets7.86.76.96.86.39.99.89.38.07.910.610.85.77.77.79.39.18.99.47.17.27.57.57.06.97.17.57.88.08.08.79.29.49.29.18.98.58.46.6

Stockholders Equity

us-gaap:StockholdersEquity



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-312008-12-312007-12-31
Value89093891996385685094192198798386385310260-10-52-112-132-159-170-139161152197236361321328319306261214171181194215210187112-2117
Percentage of StockholdersEquity100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets13.113.113.714.312.813.715.815.014.313.512.312.23.12.6-0.5-2.3-5.1-6.1-7.6-9.1-7.88.58.611.013.520.319.820.420.418.917.715.612.713.214.916.716.514.59.30.00.0

us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-31
Value-8-8-5-5-5-5-5-5-5-5-5-5-5-5-4-4-4-4-5-5-5-6
Percentage of StockholdersEquity-1.0-0.9-0.6-0.6-0.7-0.7-0.6-0.6-0.6-0.6-0.7-0.7-5.6-9.545.09.04.33.63.73.54.3-3.7
Percentage of Assets-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.1-0.2-0.2-0.2-0.2-0.2-0.2-0.3-0.3-0.3-0.3
Percentage of Assets us-gaap:AccumulatedDefinedBenefitPlansAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedGainLossNetCashFlowHedgeParent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-31
Value-91-47-58-46-22-71616122-4-6-3-1
Percentage of StockholdersEquity-10.3-5.0-6.3-4.9-2.6-0.91.81.81.30.3-0.6-0.7-3.9-2.3
Percentage of Assets-1.4-0.7-0.9-0.7-0.3-0.10.30.30.20.0-0.1-0.1-0.1-0.1
Percentage of Assets us-gaap:AccumulatedGainLossNetCashFlowHedgeParent0.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedOtherComprehensiveIncome



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-168-77-81-73-61-39-22-24321-1-48-47-49-47-48-49-44-49-35-42-218551411-123
Percentage of StockholdersEquity-19.0-8.3-8.8-7.6-7.2-4.7-2.4-2.63.30.2-0.1-5.7-46.5-81.6455.290.943.933.530.920.930.3-13.12.31.93.27.810.18.2135.1
Percentage of Assets-2.5-1.1-1.2-1.1-0.9-0.6-0.4-0.40.50.0-0.0-0.7-1.4-2.1-2.1-2.1-2.2-2.0-2.4-1.9-2.4-1.10.50.40.41.10.90.00.0
Percentage of Assets us-gaap:AccumulatedOtherComprehensiveIncome0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AccumulatedTranslationAdjustment



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-31
Value-68-22-17-20-33-26-33-342549-37-38-42-34-31-34-36-35-27-33-13
Percentage of StockholdersEquity-7.7-2.4-1.9-2.2-3.9-3.1-3.6-3.82.60.51.1-4.3-37.1-69.8325.058.830.627.622.016.024.0-8.3
Percentage of Assets-1.0-0.3-0.3-0.3-0.5-0.4-0.6-0.60.40.10.1-0.5-1.1-1.8-1.5-1.3-1.6-1.7-1.7-1.5-1.9-0.7
Percentage of Assets us-gaap:AccumulatedTranslationAdjustment0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:AdditionalPaidInCapital



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value1922189918851868185218231810179817881761863818764718679646611590570545
Percentage of StockholdersEquity216.0202.4205.0193.9216.2214.4192.3195.1181.1179.11417.8-618.2474.3198.9221.7355.8327.1525.0-2677.23116.2
Percentage of Assets28.326.628.027.827.629.430.529.225.924.236.537.640.140.341.946.947.648.60.00.0
Percentage of Assets us-gaap:AdditionalPaidInCapital0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:CommonStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.0
Percentage of StockholdersEquity0.00.00.00.00.00.00.00.00.00.00.1-0.10.00.00.00.00.00.1-0.40.4
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0
Percentage of Assets us-gaap:CommonStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:RetainedEarnings



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value20631988192118791776175516711659161316471644145012751091908742605509426322
Percentage of StockholdersEquity231.8211.9208.9195.0207.3206.3177.5180.1163.4167.52700.5-1095.7791.1302.0296.2408.5323.8452.7-2000.51843.4
Percentage of Assets30.327.828.527.926.528.328.127.023.322.669.466.767.061.256.053.847.141.90.00.0
Percentage of Assets us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

us-gaap:TreasuryStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312016-12-312015-12-312014-12-312013-12-312012-12-312011-12-312010-12-312009-12-312008-12-312007-12-31
Value-2927-2871-2805-2711-2710-2688-2517-2512-2446-2426-2396-2357-1857-1457-1287-1213-1045-999-1016-874
Percentage of StockholdersEquity-328.8-305.9-305.1-281.3-316.3-316.0-267.4-272.7-247.8-246.8-3936.81780.4-1152.3-403.3-419.9-667.5-558.7-887.84769.9-4995.1
Percentage of Assets-43.0-40.2-41.6-40.3-40.4-43.4-42.4-40.8-35.4-33.3-101.2-108.4-97.5-81.7-79.4-87.9-81.3-82.20.00.0
Percentage of Assets us-gaap:TreasuryStock0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Common Stock Value

us-gaap:CommonStockValue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value82000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.082000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.078000.0
Percentage of CommonStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Retained Earnings Accumulated Deficit

us-gaap:RetainedEarningsAccumulatedDeficit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value206319881921187917761755167116591613164715391588168016441577153814901450138413541303127512151182112910911029991945908849818776742697667634605509
Percentage of RetainedEarningsAccumulatedDeficit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets30.327.828.527.926.528.328.127.023.322.622.022.749.969.469.366.867.466.766.272.872.867.068.765.864.261.263.261.460.356.057.459.357.553.853.551.549.847.141.9

Treasury Stock Value

us-gaap:TreasuryStockValue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value29272871280527112710268825172512244624262424241824102396239123912387235723012284218218571816173716341457142213631318128712681268126412131146109410601045999
Percentage of TreasuryStockValue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets43.040.241.640.340.443.442.440.835.433.334.634.671.6101.2105.0103.8107.9108.4110.1122.8122.097.5102.796.793.081.787.484.584.179.485.791.993.787.987.984.483.281.382.2

Accumulated Other Comprehensive Income Loss Net Of Tax

us-gaap:AccumulatedOtherComprehensiveIncomeLossNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value-168-77-81-73-61-39-22-24321-1-48-47-49-47-48-49-44-49-35-42-21-298862258385514161411
Percentage of AccumulatedOtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of Assets-2.5-1.1-1.2-1.1-0.9-0.6-0.4-0.40.50.0-0.0-0.7-1.4-2.1-2.1-2.1-2.2-2.0-2.4-1.9-2.4-1.1-0.10.60.50.50.40.10.20.40.60.30.60.40.41.11.31.10.9

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value55822192273545249174222149112-298312814887911614357112213616197110980187911288-24796469-7
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax5.56.921.921.23.74.127.017.40.32.218.113.3-4.711.922.524.31.512.323.426.21.212.226.126.23.74.815.029.220.35.118.532.524.2-7.520.721.922.1-2.7

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-24-62-36-39-22-5673383-16-35-46-2523-140-17-11-47-7-10-207-11-11-15-6-16-124-9-13-10-23-7-18-14-5-3-9-4-4-15
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-2.4-5.2-3.6-3.7-2.3-5.28.038.3-1.7-3.5-5.6-299.1-22.4-2.5-1.9-7.8-1.3-1.7-41.6-2.2-2.5-2.6-1.4-3.2-27.9-2.4-2.9-2.9-5.8-1.9-4.3-4.1-1.6-1.1-2.5-1.5-1.5-5.1

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-68-53-90-118-23-43-266-618-329-65-801768917-43-97-6026-66115-62-54-12-78-85-32-36-140-41-17-75-61-6717-98-45-4314
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-6.7-4.4-9.1-11.1-2.4-4.0-28.9-61.7-34.2-6.5-9.7209.6146.7-6.2-16.9-9.94.8-10.323.1-11.3-11.5-2.1-16.6-16.5-7.2-9.1-3.00.2-10.5-4.8-17.6-17.8-18.55.4-25.6-15.3-13.75.0

Net Cash Provided By Used In Operating Activities

us-gaap:NetCashProvidedByUsedInOperatingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value55822192273545249174222149112-298312814887911614357112213616197110980187911288-24796469-7
Percentage of NetCashProvidedByUsedInOperatingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax5.56.921.921.23.74.127.017.40.32.218.113.3-4.711.922.524.31.512.323.426.21.212.226.126.23.74.815.029.220.35.118.532.524.2-7.520.721.922.1-2.7

Net Income Loss

us-gaap:NetIncomeLoss



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value75674110320841146-19107-48-9236663047406530512859335337384636583141344530322936202019
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax7.45.64.19.72.17.71.34.6-2.010.6-5.8-10.95.89.55.37.97.210.26.19.36.010.17.210.28.49.310.49.012.48.410.49.310.58.88.88.99.66.86.46.6

us-gaap:StatementEquityComponents

us-gaap:RetainedEarnings



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value75674110320841146-19
Percentage of NetIncomeLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax7.45.64.19.72.17.71.34.6-2.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:RetainedEarnings0.00.00.00.00.00.00.00.00.0

Depreciation Depletion And Amortization

us-gaap:ConsolidationItems

us-gaap:DepreciationDepletionAndAmortization

it:CorporateAndReconcilingItems



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-30
Value5453525253526866687168831615151515151110
Percentage of DepreciationDepletionAndAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Net Cash Provided By Used In Investing Activities

us-gaap:NetCashProvidedByUsedInInvestingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-24-62-36-39-22-5673383-16-35-46-2523-140-17-11-47-7-10-207-11-11-15-6-16-124-9-13-10-23-7-18-14-5-3-9-4-4-15
Percentage of NetCashProvidedByUsedInInvestingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-2.4-5.2-3.6-3.7-2.3-5.28.038.3-1.7-3.5-5.6-299.1-22.4-2.5-1.9-7.8-1.3-1.7-41.6-2.2-2.5-2.6-1.4-3.2-27.9-2.4-2.9-2.9-5.8-1.9-4.3-4.1-1.6-1.1-2.5-1.5-1.5-5.1

Net Cash Provided By Used In Financing Activities

us-gaap:NetCashProvidedByUsedInFinancingActivities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-68-53-90-118-23-43-266-618-329-65-801768917-43-97-6026-66115-62-54-12-78-85-32-36-140-41-17-75-61-6717-98-45-4314
Percentage of NetCashProvidedByUsedInFinancingActivities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of RevenueFromContractWithCustomerExcludingAssessedTax-6.7-4.4-9.1-11.1-2.4-4.0-28.9-61.7-34.2-6.5-9.7209.6146.7-6.2-16.9-9.94.8-10.323.1-11.3-11.5-2.1-16.6-16.5-7.2-9.1-3.00.2-10.5-4.8-17.6-17.8-18.55.4-25.6-15.3-13.75.0

Proceeds From Issuance Of Long Term Debt

us-gaap:ProceedsFromIssuanceOfLongTermDebt



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value000-3035000001401930955-32-8276070-1013055265225-123151200127-3247-5-3040173-361152
Percentage of ProceedsFromIssuanceOfLongTermDebt0.00.00.0100.0100.00.00.00.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Repayments Of Long Term Debt

us-gaap:RepaymentsOfLongTermDebt



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0009018-1092615533046421910118778155555519033120077775555252212114
Percentage of RepaymentsOfLongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Payments For Repurchase Of Common Stock

us-gaap:PaymentsForRepurchaseOfCommonStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312016-01-312015-12-312015-09-302015-06-302015-03-312015-01-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value7357941441568672843112160645756111173242447911119548224777705335512313935
Percentage of PaymentsForRepurchaseOfCommonStock100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Repayments Of Long Term Debt

us-gaap:RepaymentsOfLongTermDebt



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value0009018-1092615533046421910118778155555519033120077775555252212114
Percentage of RepaymentsOfLongTermDebt100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0
Percentage of LongTermDebtAndCapitalLeaseObligations0.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0

Debt Instrument Interest Rate Stated Percentage

Effective Income Tax Rate Continuing Operations

us-gaap:EffectiveIncomeTaxRateContinuingOperations



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value0.2250.1570.2210.1360.0120.5430.690.3840.5430.6920.2220.3540.2490.0260000000000000230.3190.3790.334-0.0190000000000000170.4140.3570.3590.0140000000000000120.2710.3310.3340.3250.350.292-0.0250000000000000220.330.3140.3210.00200000000000000180.3140.3310.315-0.036000000000000030.3170.339
Percentage of EffectiveIncomeTaxRateContinuingOperations100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number

Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price

Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants In Period

Share Based Compensation

us-gaap:ShareBasedCompensation



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value2511121331101014301114302210911159910169861377128971087799769
Percentage of ShareBasedCompensation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Tax Liabilities

Deferred Tax Assets Net

Unrecognized Tax Benefits

us-gaap:UnrecognizedTaxBenefits



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-312009-12-31
Value103102878780906260636072644237313127252221212018171514181818172019191819171513
Percentage of UnrecognizedTaxBenefits100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Deferred Tax Assets Valuation Allowance

Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions

Operating Lease Right Of Use Asset

us-gaap:OperatingLeaseRightOfUseAsset



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312019-01-01
Value678702652637634651
Percentage of OperatingLeaseRightOfUseAsset100.0100.0100.0100.0100.0100.0

Cash And Cash Equivalents Period Increase Decrease

Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312015-12-31
Value2272803062181491582131592275676486321271499412
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:BusinessCombinationAcquisitionandIntegrationRelatedCosts



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value15102101720591630981391688106355663000
Percentage of BusinessCombinationAcquisitionandIntegrationRelatedCosts100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ConsolidationItems

it:CorporateAndReconcilingItems



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-30
Value151021017195916309813916881063
Percentage of BusinessCombinationAcquisitionandIntegrationRelatedCosts100.0100.0100.0100.0100.0100.0100.199.899.9100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:InterestExpenseandOtherNonoperatingIncome



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-30
Value27-15816242525273634343744523644054322
Percentage of InterestExpenseandOtherNonoperatingIncome100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:OperatingLeaseRightOfUseAssetReductionInCarryingAmount



Period End2020-03-312019-03-31
Value2220
Percentage of OperatingLeaseRightOfUseAssetReductionInCarryingAmount100.0100.0

us-gaap:ConsolidationItems, us-gaap:Range

it:SegmentReportingInformationPercentofTargetBonusChargesAllocatedtoSegments

us-gaap:OperatingSegments, srt:Maximum



Period End2020-03-31
Value1.0
Percentage of SegmentReportingInformationPercentofTargetBonusChargesAllocatedtoSegments100.0

it:TreasuryStockAveragePricePaidPerShare



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-31
Value00000000000000000000049000000
Percentage of TreasuryStockAveragePricePaidPerShare100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value251112133110101430
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value251112133110101430
Percentage of AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AllocatedShareBasedCompensationExpense



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value25111313311010143010143122109111599101698613777
Percentage of AllocatedShareBasedCompensationExpense100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AwardType

it:CommonStockEquivalents



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302012-06-302011-06-30
Value200000.0100000.0200000.0200000.0200000.0200000.0100000.0200000.0200000.0200000.0100000.0100000.0200000.0200000.0200000.0200000.0200000.0100000.0
Percentage of AllocatedShareBasedCompensationExpense0.80.91.51.50.62.00.91.40.61.80.70.30.91.92.11.80.00.0

it:RetirementEligibleEmployeesEquityAward



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-30
Value1100020-10217026142310331022711
Percentage of AllocatedShareBasedCompensationExpense46.2-2.73.13.865.7-17.62.814.657.62.814.619.464.226.334.266.531.236.462.933.030.455.824.323.6

us-gaap:RestrictedStockUnitsRSU



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-312012-09-302012-06-302011-12-312011-09-302011-06-30
Value2310111227991227-61132919989137891487511665666766
Percentage of AllocatedShareBasedCompensationExpense92.491.090.891.687.191.291.689.688.0-565.191.795.286.785.884.286.587.785.786.586.986.287.286.482.684.883.683.881.90.00.00.00.00.00.0

us-gaap:StockAppreciationRightsSARS



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302012-12-312012-09-302012-06-302011-09-302011-06-30
Value101030013011211111112111111112110
Percentage of AllocatedShareBasedCompensationExpense6.88.17.76.912.36.97.59.011.33.77.64.512.412.313.711.711.013.211.511.212.611.711.414.513.814.414.916.70.00.00.00.00.0

us-gaap:IncomeStatementLocation

us-gaap:AcquisitionRelatedCosts



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-30
Value00000001114000
Percentage of AllocatedShareBasedCompensationExpense0.00.81.50.3-4.92.81.44.28.346.50.00.00.0

us-gaap:CostOfSales



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value1256611546114669444744464435333
Percentage of AllocatedShareBasedCompensationExpense48.248.647.747.335.552.043.946.536.939.442.420.341.246.248.444.149.049.546.943.941.343.645.553.642.043.143.244.4

us-gaap:SellingGeneralAndAdministrativeExpenses



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value135662045718471013546745695438444
Percentage of AllocatedShareBasedCompensationExpense51.850.551.551.164.247.153.352.158.943.149.333.258.853.851.655.951.050.553.156.158.756.454.546.458.057.556.855.6

us-gaap:AmortizationOfFinancingCosts



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value11111118113900010000010000000000000000
Percentage of AmortizationOfFinancingCosts100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AmortizationOfIntangibleAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value3232313233345050515351656666662222211111110000222222
Percentage of AmortizationOfIntangibleAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-09-302011-06-302011-03-312010-09-302010-06-30
Value000011110000000000000000010111
Percentage of AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect



Period End2020-03-312019-12-312019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value-37-33-10-5456-61-343-78-2-642765
Percentage of CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseExcludingExchangeRateEffect100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerLiabilityRevenueRecognized



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value658124675708650123642651605
Percentage of ContractWithCustomerLiabilityRevenueRecognized100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DeferredIncomeTaxExpenseBenefit



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value25-20-1-23-2541321-39-116-21-66-1111-121-25-85-31-5-27-140-1-1-459-104-500
Percentage of DeferredIncomeTaxExpenseBenefit100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DefinedBenefitPlanNetPeriodicBenefitCost



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value110001000100010001000100000000000000000
Percentage of DefinedBenefitPlanNetPeriodicBenefitCost100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Depreciation



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value22212020191817161618171810999888878777777666566666666
Percentage of Depreciation100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DepreciationAndAmortization



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value545352525352686668716883161515151515129101010988877677888889
Percentage of DepreciationAndAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeGainLossOnDerivativeNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value-150-204110-86120-2-113-1-2-26-2-2-1-2110-3111
Percentage of DerivativeGainLossOnDerivativeNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncomeStatementLocation

it:InterestIncomeExpense



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value-3122000-2-2
Percentage of DerivativeGainLossOnDerivativeNet20.2-52.5-759.355.3-294.5-4.2-15.0552.379.9

it:OtherGainLossNet



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value-12-4-21-1-87100
Percentage of DerivativeGainLossOnDerivativeNet79.8152.5859.344.7394.5104.2115.0-452.320.113.7

us-gaap:DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0000-2613250000
Percentage of DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax0.00.00.00.0100.0100.0100.0100.00.00.00.00.0

us-gaap:EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-31
Value-157-4000-3-63-21746
Percentage of EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount



Period End2020-03-312019-03-31
Value-5-7
Percentage of EffectiveIncomeTaxRateReconciliationShareBasedCompensationExcessTaxBenefitAmount100.0100.0

us-gaap:FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-06-302016-03-31
Value-370-6-128-10-9-2415021-20000
Percentage of FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:ComputerSoftwareIntangibleAsset



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-06-302016-03-31
Value-100000000-5100000
Percentage of FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss3.163.02.93.23.23.00.73.33.1-632.28.631.613.413.5-33.3-2125.0

us-gaap:CustomerRelationships



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-06-302016-03-31
Value-360-6-118-9-6-2215111100000
Percentage of FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss96.393.594.996.696.193.470.991.996.41330.153.1-12.460.563.4184.55100.0

us-gaap:MediaContent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-06-302016-03-31
Value000000-300-47-10000
Percentage of FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss0.5-8.70.00.00.02.437.13.41.6-497.436.583.411.810.9-83.3-3750.0

us-gaap:OtherIntangibleAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value-72000.022000.0-141000.0-26000.061000.0-124000.0828000.0-329000.0-171000.0-885000.0
Percentage of FiniteLivedIntangibleAssetsForeignCurrencyTranslationGainLoss0.2-47.82.10.20.71.2-8.71.4-1.1-100.5

us-gaap:GainLossOnSaleOfBusiness



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-30
Value0000-2613250000
Percentage of GainLossOnSaleOfBusiness0.00.00.00.0100.0100.0100.0100.00.00.00.00.0

us-gaap:GoodwillForeignCurrencyTranslationGainLoss



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value-10923-16517-102602
Percentage of GoodwillForeignCurrencyTranslationGainLoss100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementBusinessSegments

it:Conferences



Period End2020-03-31
Value-1
Percentage of GoodwillForeignCurrencyTranslationGainLoss12.7

it:Consulting



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value-64000.0-149000.0-96000.047000.09000.0-863000.0528000.0906000.0272000.0197000.0
Percentage of GoodwillForeignCurrencyTranslationGainLoss0.6-1.6-0.4-0.30.2-4.8-5.23.433.57.4

it:ResearchSegment



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-31
Value-8923-16518-171912
Percentage of GoodwillForeignCurrencyTranslationGainLoss86.7101.5100.199.994.2103.1177.772.9206.589.5

us-gaap:IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value961105391211103775-4228-61-142481064477609651794492467956567151774660506644484246293027
Percentage of IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInAccountsPayableAndAccruedLiabilities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value-269127628-218134494-1337813779-1091033850-1361105835-1211143946-104-85743020-88891622-847521
Percentage of IncreaseDecreaseInAccountsPayableAndAccruedLiabilities100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInAccountsReceivable



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-135281-74-62-78287-91-24-56353-29-125794-46119101-43-3-9113-34-7417-92849-3974-413-25636-12-8
Percentage of IncreaseDecreaseInAccountsReceivable100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInDeferredCharges



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-1765-12-18-469-16-22064-22-3312-8-731-2-7-836-6-9-84-2222-6-318-3-4-317-2-7-5
Percentage of IncreaseDecreaseInDeferredCharges100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInDeferredRevenue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-2611122-3785118-181076184307592-1672779-17161974121511655110131134173810252533-430
Percentage of IncreaseDecreaseInDeferredRevenue100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInOtherOperatingAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value-5-19-22128110-9-14-58590161-236-51241-125-221-612002-2-201-22276
Percentage of IncreaseDecreaseInOtherOperatingAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value12-1917-7-8-13-182953-459175-21447-8-2925-522-201804-48-2616-94-79-28
Percentage of IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:IncrementalCommonSharesAttributableToShareBasedPaymentArrangements



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value001110110100101010111011111102220223033
Percentage of IncrementalCommonSharesAttributableToShareBasedPaymentArrangements100.0100.0100.0100.0100.0100.0100.0100.00.0100.00.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax



Period End2020-03-312019-09-302019-03-312018-09-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-31
Value-93-6-2013-155-21-19-120003-1-3
Percentage of OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value0000000000-10000000-4000000
Percentage of OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax-0.0-0.00.0-0.00.00.00.00.00.00.00.00.00.00.030.5-0.00.0-0.021.6-0.00.0-0.0-27.80.0-0.0

us-gaap:AccumulatedGainLossNetCashFlowHedgeParent



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value-47-10-23-120490-3
Percentage of OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax50.4152.80.064.054.30.00.00.00.0

us-gaap:AccumulatedTranslationAdjustment



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value-46312-700204614-8-332-1-76-20-15-120014-1
Percentage of OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax49.6-52.80.036.045.70.00.00.00.00.00.00.00.00.0-40.451.4110.691.578.1100.0113.267.8142.4109.6121.2

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax



Period End2020-03-312019-09-302019-06-302019-03-312018-06-302018-03-31
Value-44-11-24-14310
Percentage of OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax100.0100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-31
Value-9111-11-24-22
Percentage of OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax100.0100.0100.0100.0100.0

us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

us-gaap:OtherLiabilities, us-gaap:InterestRateSwap, us-gaap:DesignatedAsHedgingInstrument



Period End2020-03-312019-12-312019-09-302019-06-302019-03-31
Value-9111-11-24-22
Percentage of OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax100.0100.0100.0100.0100.0

us-gaap:OtherComprehensiveIncomeLossNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-30
Value-913-7-11-21-171-5630247-11-101-54-136-21-19-111040-3-25-420-8-1
Percentage of OtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value0000000000-10001000-4000000
Percentage of OtherComprehensiveIncomeLossNetOfTax-0.1-0.5-0.3-0.23.9-0.10.20.1-4.62.656.716.92.7-0.721.3-0.40.8-0.322.2-0.11.07.20.00.1-0.2

us-gaap:AccumulatedGainLossNetCashFlowHedgeParent



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value-44-11-24-1403101-2
Percentage of OtherComprehensiveIncomeLossNetOfTax49.1146.2207.566.825.6-6.532.92.7201.5

us-gaap:AccumulatedOtherComprehensiveIncome



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-31
Value-91-7-11-211-563047-11-101-54-136-21
Percentage of OtherComprehensiveIncomeLossNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AccumulatedTranslationAdjustment



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value-46312-70-60204614-8-332-1-76-20-15-120014-1
Percentage of OtherComprehensiveIncomeLossNetOfTax50.9-45.6-107.133.370.5106.666.997.2-96.9236.1440.1-1384.5233.7-41.1-26.857.892.795.080.7105.362.5-134.30.093.9301.2

us-gaap:OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-31
Value02000000000001000-1000000000000
Percentage of OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsForCapitalImprovements



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-302010-03-31
Value2453363920622422173533301012111861012111112699913101371814539443
Percentage of PaymentsForCapitalImprovements100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PaymentsToAcquireBusinessesNetOfCashAcquired



Period End2020-03-312019-12-312019-03-312018-12-312017-12-312015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-31
Value023202640002051010
Percentage of PaymentsToAcquireBusinessesNetOfCashAcquired0.0100.0100.00.0100.00.00.0100.00.0100.0100.00.0

us-gaap:ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-30
Value5443533343223222211121122111352121448
Percentage of ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax



Period End2020-03-312019-09-302019-03-312018-09-302015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value-2110-1-1-100000000
Percentage of ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents

us-gaap:AccumulatedDefinedBenefitPlansAdjustment



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value-79000.0-41000.0-41000.0-42000.0-53000.0-55000.0-56000.0-52000.0-49000.0-48000.0-36000.0-37000.0-38000.0-37000.0-51000.0-53000.0-53000.0-53000.0-14000.0-15000.0-14000.0-15000.0-11000.0-6000.0-1000.0
Percentage of ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax3.3-3.90.0-2.6-12.70.00.00.00.00.00.00.00.00.03.13.14.96.62.22.42.22.41.81.00.2

us-gaap:AccumulatedGainLossNetCashFlowHedgeParent



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-30
Value-2111000-1-1
Percentage of ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax96.7103.80.0102.6148.80.00.00.00.0

us-gaap:AccumulatedTranslationAdjustment



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-30
Value00000600000000000000000000
Percentage of ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax-0.00.00.00.0-36.10.00.00.00.00.00.00.00.00.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0-0.0

us-gaap:StatementBusinessSegments, us-gaap:SubsequentEventType

us-gaap:RestructuringAndRelatedCostNumberOfPositionsEliminatedPeriodPercent

it:Conferences, us-gaap:SubsequentEvent



Period End2020-04-30
Value0.45
Percentage of RestructuringAndRelatedCostNumberOfPositionsEliminatedPeriodPercent100.0

us-gaap:SubsequentEventType

us-gaap:SubsequentEvent



Period End2020-04-30
Value0.03
Percentage of RestructuringAndRelatedCostNumberOfPositionsEliminatedPeriodPercent6.7

us-gaap:StockGrantedDuringPeriodValueSharebasedCompensation



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value54453-14
Percentage of StockGrantedDuringPeriodValueSharebasedCompensation100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents

us-gaap:AdditionalPaidInCapital



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value-133-21-4-4
Percentage of StockGrantedDuringPeriodValueSharebasedCompensation-31.784.878.2-57.550.6400.4-103.7

us-gaap:TreasuryStock



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-31
Value7007138
Percentage of StockGrantedDuringPeriodValueSharebasedCompensation131.715.221.8157.549.4-300.4203.7

us-gaap:StockRepurchasedDuringPeriodValue



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value63679412917176828
Percentage of StockRepurchasedDuringPeriodValue100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:StatementEquityComponents

us-gaap:TreasuryStock



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value63679412917176828
Percentage of StockRepurchasedDuringPeriodValue100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:TreasuryStockSharesAcquired



Period End2020-03-312019-09-302019-06-302019-03-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-09-302016-06-302016-03-312015-09-302015-06-302015-03-312014-09-302014-06-302014-03-312013-09-302013-06-302013-03-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312010-09-302010-06-30
Value0000000000000014112186500012101001
Percentage of TreasuryStockSharesAcquired100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:DebtLongtermandShorttermCombinedAmountGross



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-31
Value220622072207220723282312220224643018332333873467702
Percentage of DebtLongtermandShorttermCombinedAmountGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

it:NumberofEnterprisesServed



Period End2020-03-312017-06-30
Value15000.011000.0
Percentage of NumberofEnterprisesServed100.0100.0

us-gaap:AccountsReceivableGrossCurrent



Period End2020-03-312019-12-312019-09-302018-12-31
Value1157133410361262
Percentage of AccountsReceivableGrossCurrent100.0100.0100.0100.0

us-gaap:AdditionalPaidInCapital



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value192218991885186818521823181017981788176117481732880863851847832818806795781764754743733718707698689679671661651646636628619611590
Percentage of AdditionalPaidInCapital100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:AllowanceForDoubtfulAccountsReceivableCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312011-12-312010-12-312009-12-31
Value98777777712109777776666667770666778
Percentage of AllowanceForDoubtfulAccountsReceivableCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0

us-gaap:AssetsFairValueDisclosure



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302011-12-31
Value6577707073679594939343414038373535343235353533343332302929274138
Percentage of AssetsFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:ForeignExchangeForward, us-gaap:FairValueInputsLevel2



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-31
Value01000100020000
Percentage of AssetsFairValueDisclosure0.22.00.10.10.31.90.20.30.22.20.10.10.10.4

us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:FairValueInputsLevel1



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-312015-12-312014-12-312013-12-31
Value52881082910877
Percentage of AssetsFairValueDisclosure8.52.912.712.614.413.231.126.824.921.823.8

us-gaap:FairValueInputsLevel2



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value60746161625979777664313029282725252625282727262624
Percentage of AssetsFairValueDisclosure91.597.187.387.485.686.883.181.382.168.971.472.272.373.272.972.272.575.176.579.177.078.277.778.176.2

us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument

us-gaap:FairValueInputsLevel2, it:PlanAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value59736161625756545959313029272625252525282727262624
Percentage of AssetsFairValueDisclosure91.295.087.287.385.484.958.957.363.563.171.272.172.272.872.872.172.573.376.479.077.076.977.778.175.8

us-gaap:ContractWithCustomerAssetGross



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value192124112011861262986109111421162
Percentage of ContractWithCustomerAssetGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerLiability



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value1864195218181812185417661667170517351646
Percentage of ContractWithCustomerLiability100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerLiabilityCurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value1847192818031796183717451650168717191630
Percentage of ContractWithCustomerLiabilityCurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:ContractWithCustomerLiabilityNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-31
Value17241516172116171616
Percentage of ContractWithCustomerLiabilityNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:CreditFacility

us-gaap:DebtInstrumentCarryingAmount

us-gaap:RevolvingCreditFacility



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302015-12-31
Value1751481209218515527270310595640500270115147230440
Percentage of DebtInstrumentCarryingAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DebtInstrument, us-gaap:LongtermDebtType

it:EconomicDevelopmentLoan1, it:ConnecticutEconomicDevelopmentProgram



Period End2020-03-312019-12-312019-09-302019-06-302019-03-31
Value11111
Percentage of DebtInstrumentCarryingAmount0.81.01.42.01.0

us-gaap:LongtermDebtType

it:BankTermLoan



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302015-12-31
Value122512521280130813361355137313921410142914471466585585592600380
Percentage of DebtInstrumentCarryingAmount700.1846.61067.31422.5722.4874.25087.5515.6455.1240.2226.2293.3216.7508.7401.7260.986.4

it:OtherLongTermDebt



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-31
Value666662
Percentage of DebtInstrumentCarryingAmount3.74.45.67.43.71.3

us-gaap:SeniorNotes



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-302016-12-31
Value8008008008008008008008008008008008008000
Percentage of DebtInstrumentCarryingAmount457.1540.5666.7869.6432.4516.12963.0296.3258.1134.5125.0160.00.00.0

us-gaap:LongtermDebtType

us-gaap:DebtInstrumentFaceAmount

us-gaap:SeniorNotes



Period End2020-03-31
Value800
Percentage of DebtInstrumentFaceAmount100.0

us-gaap:DebtIssuanceCostsLineOfCreditArrangementsNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302015-12-31
Value2223252728303233424446492888-80
Percentage of DebtIssuanceCostsLineOfCreditArrangementsNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0

us-gaap:DebtLongtermAndShorttermCombinedAmount



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302016-12-31
Value218421832181218022992281217024302975327833413417694
Percentage of DebtLongtermAndShorttermCombinedAmount100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeAssetsLiabilitiesAtFairValueNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value-126-64-80-65-30-122221163-8-10-6-2-14-20-17-4-13-4-4-2-3-4-5-6-7-7-9-9-11-10-9-9-11-6-5
Percentage of DerivativeAssetsLiabilitiesAtFairValueNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

it:AccruedLiabilitiesCurrent, us-gaap:ForeignExchangeForward, us-gaap:Nondesignated



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302014-12-31
Value0000-100000000000000
Percentage of DerivativeAssetsLiabilitiesAtFairValueNet0.40.30.71.115.4-1.9-1.8-2.91.11.02.312.00.40.50.7-4.80.50.2-8.9

us-gaap:OtherLiabilities, us-gaap:InterestRateSwap, us-gaap:DesignatedAsHedgingInstrument



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value-126-64-80-64-30-10-8-10-6-2-14-20-17-5-13-4-4-2-3-4-5-6-7-7-9-10-11-10-9
Percentage of DerivativeAssetsLiabilitiesAtFairValueNet99.6100.199.799.398.984.698.999.097.788.099.699.599.3104.899.599.899.3108.999.599.999.999.199.399.399.8100.097.9100.3101.8

us-gaap:Range, us-gaap:DerivativeInstrumentRisk

us-gaap:DerivativeFixedInterestRate

srt:Maximum, us-gaap:InterestRateSwap



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312017-12-31
Value0.03040.03040.03040.02130.02130.0213
Percentage of DerivativeFixedInterestRate100.0100.0100.0100.0100.0100.0

srt:Minimum, us-gaap:InterestRateSwap



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312017-12-31
Value0.02130.02130.02130.01530.01530.0153
Percentage of DerivativeFixedInterestRate70.170.170.171.871.871.8

us-gaap:DerivativeNotionalAmount



Period End2020-03-312019-12-312019-09-302018-12-31
Value1627200416033027
Percentage of DerivativeNotionalAmount100.0100.0100.0100.0

us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

it:AccruedLiabilitiesCurrent, us-gaap:ForeignExchangeForward, us-gaap:Nondesignated



Period End2020-03-312019-09-302018-12-31
Value227203927
Percentage of DerivativeNotionalAmount14.012.730.6

us-gaap:OtherLiabilities, us-gaap:InterestRateSwap, us-gaap:DesignatedAsHedgingInstrument



Period End2020-03-312019-12-312019-09-302018-12-31
Value1400140014002100
Percentage of DerivativeNotionalAmount86.069.887.369.4

us-gaap:DerivativeNumberOfInstrumentsHeld



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value47.0180.044.045.063.0142.055.049.051.0142.034.030.028.087.019.025.024.0105.024.028.026.078.020.023.023.090.033.039.044.069.031.036.029.063.018.021.066.0
Percentage of DerivativeNumberOfInstrumentsHeld100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:BalanceSheetLocation, us-gaap:DerivativeInstrumentRisk, us-gaap:HedgingDesignation

it:AccruedLiabilitiesCurrent, us-gaap:ForeignExchangeForward, us-gaap:Nondesignated



Period End2020-03-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302014-12-31
Value43.040.038.056.0135.048.044.046.029.025.023.084.016.022.021.0102.021.025.077.0
Percentage of DerivativeNumberOfInstrumentsHeld91.590.984.488.995.187.389.890.285.383.382.196.684.288.087.597.187.589.398.7

us-gaap:OtherLiabilities, us-gaap:InterestRateSwap, us-gaap:DesignatedAsHedgingInstrument



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302011-12-31
Value4.04.04.07.07.07.05.05.05.03.03.03.03.03.03.03.02.01.01.01.01.01.01.01.01.01.01.01.01.0
Percentage of DerivativeNumberOfInstrumentsHeld8.52.29.115.611.14.914.716.717.93.415.812.012.52.912.510.77.71.35.04.34.31.13.02.62.31.43.22.81.6

us-gaap:DerivativeInstrumentRisk

us-gaap:InterestRateSwap



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312016-12-312016-09-302016-06-302016-03-312015-09-302015-06-30
Value004550000000
Percentage of DerivativeNumberOfInstrumentsHeld8.52.29090909.111111111.17936507.93.53.415.812.012.512.510.7

us-gaap:FiniteLivedIntangibleAssetsAccumulatedAmortization



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value399376341311299350326289243190157109463934332721151412232119171514121110-876161515510
Percentage of FiniteLivedIntangibleAssetsAccumulatedAmortization100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:ComputerSoftwareIntangibleAsset



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302011-12-31
Value666155504438423832262422108764323322111000000
Percentage of FiniteLivedIntangibleAssetsAccumulatedAmortization16.716.416.316.114.911.113.013.413.313.815.521.022.122.322.418.617.917.215.225.225.211.09.98.27.87.26.55.84.63.92.5-2.5

us-gaap:CustomerRelationships



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value2992832552322101841621411199275471916141411965411109887765-54433231
Percentage of FiniteLivedIntangibleAssetsAccumulatedAmortization75.075.474.774.670.252.849.649.049.048.747.643.342.041.942.142.242.542.143.037.437.547.048.650.651.353.354.154.956.357.158.560.361.021.820.017.961.017.7

us-gaap:MediaContent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-30
Value12119879291796347362022143322222111100000
Percentage of FiniteLivedIntangibleAssetsAccumulatedAmortization3.13.02.92.92.626.528.027.426.224.923.418.95.45.14.613.214.116.419.518.519.69.59.69.69.58.88.17.26.14.83.20.9

us-gaap:OtherIntangibleAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-31
Value211921203633302927242112
Percentage of FiniteLivedIntangibleAssetsAccumulatedAmortization5.35.36.26.512.39.69.410.311.412.713.630.7

us-gaap:FiniteLivedIntangibleAssetsGross



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value1263130112781285131513921412146614901482172217041271161151321181181114140545455512122222221122323231223
Percentage of FiniteLivedIntangibleAssetsGross100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:FiniteLivedIntangibleAssetsByMajorClass

us-gaap:ComputerSoftwareIntangibleAsset



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-03-312012-12-312012-09-302011-12-31
Value109111110110110110120122123123198196171616161616876667222222
Percentage of FiniteLivedIntangibleAssetsGross8.78.58.68.68.47.98.58.48.38.311.511.513.413.713.912.713.713.77.917.416.012.112.512.95.79.89.69.69.59.0

us-gaap:CustomerRelationships



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-31
Value110811451121112811401131114111861208120013261314726362706362622020272828271010101010777777
Percentage of FiniteLivedIntangibleAssetsGross87.888.087.887.886.681.280.880.981.180.977.077.156.954.354.453.153.453.356.449.550.551.551.351.152.946.547.747.747.948.455.630.530.530.555.630.5

us-gaap:MediaContent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-03-312012-12-312012-09-302012-06-30
Value131412121298991031041041491453329551633333333333
Percentage of FiniteLivedIntangibleAssetsGross1.11.11.01.01.07.17.07.17.07.08.78.53.03.22.57.34.54.614.48.48.56.66.66.86.816.015.615.615.415.1

us-gaap:OtherIntangibleAssets



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-312015-12-31
Value30303233515151545454483333
Percentage of FiniteLivedIntangibleAssetsGross2.42.42.62.63.93.73.73.73.73.72.828.828.4

us-gaap:DerivativeInstrumentRisk

us-gaap:InterestRateFairValueHedgeDerivativeAtFairValueNet

us-gaap:InterestRateSwap



Period End2020-03-312019-12-312018-12-312017-12-312016-12-312015-12-312014-12-31
Value-126-64-103-2-5-2
Percentage of InterestRateFairValueHedgeDerivativeAtFairValueNet100.0100.0100.0100.0100.0100.0100.0

us-gaap:LiabilitiesFairValueDisclosure



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302017-12-312016-12-312015-12-312014-12-312014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302011-12-31
Value9839819939659118588819294544424343424042414138
Percentage of LiabilitiesFairValueDisclosure100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:DerivativeInstrumentRisk, us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:ForeignExchangeForward, us-gaap:FairValueInputsLevel2



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-31
Value01000300010000
Percentage of LiabilitiesFairValueDisclosure0.10.20.00.10.10.40.10.00.00.20.00.00.01.1

us-gaap:InterestRateSwap, us-gaap:FairValueInputsLevel2



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312017-09-302017-06-302017-03-312016-12-31
Value1266480643010081062
Percentage of LiabilitiesFairValueDisclosure12.86.68.16.73.41.20.00.00.00.05.1

us-gaap:FairValueByFairValueHierarchyLevel

us-gaap:FairValueInputsLevel2



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value9839819939659118588818728759299015752455761574451444542424343
Percentage of LiabilitiesFairValueDisclosure100.0100.0100.0100.0100.0100.0100.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.00.0100.00.00.0100.0

us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument

us-gaap:FairValueInputsLevel2, it:PlanLiabilities



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302013-12-31
Value67797474716874767389484745434240393937404039383836
Percentage of LiabilitiesFairValueDisclosure6.98.17.57.77.88.08.50.00.09.70.00.00.093.80.00.00.087.60.00.00.092.60.00.084.5

us-gaap:FairValueByFairValueHierarchyLevel, us-gaap:FinancialInstrument, us-gaap:LongtermDebtType

us-gaap:FairValueInputsLevel2, us-gaap:Debt, us-gaap:SeniorNotes



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302016-12-31
Value7888358388268087768057958018378440
Percentage of LiabilitiesFairValueDisclosure80.285.184.485.688.890.491.40.00.090.20.00.0

us-gaap:OperatingLeaseLiabilityNoncurrent



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312017-12-312016-12-31
Value81383277676876916511538
Percentage of OperatingLeaseLiabilityNoncurrent100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:OtherDeferredCostsNet



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302010-12-31
Value24026519721123123516618320720514314313914111211111812493981041158088971067777828765687578606571
Percentage of OtherDeferredCostsNet100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:PreferredStockSharesAuthorized



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value555555555555555555555555555555000555555555
Percentage of PreferredStockSharesAuthorized100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:Range, us-gaap:SubsequentEventType

us-gaap:RestructuringAndRelatedCostExpectedCost1

srt:Maximum, us-gaap:SubsequentEvent



Period End2020-04-30
Value6
Percentage of RestructuringAndRelatedCostExpectedCost1100.0

srt:Minimum, us-gaap:SubsequentEvent



Period End2020-04-30
Value5
Percentage of RestructuringAndRelatedCostExpectedCost183.3

us-gaap:RevenueRemainingPerformanceObligation



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-31
Value31003200290028002700270042122001060
Percentage of RevenueRemainingPerformanceObligation100.0100.0100.0100.0100.0100.0100.0100.0100.0

us-gaap:TreasuryStockShares



Period End2020-03-312019-12-312019-09-302019-06-302019-03-312018-12-312018-09-302018-06-302018-03-312017-12-312017-09-302017-06-302017-03-312016-12-312016-09-302016-06-302016-03-312015-12-312015-09-302015-06-302015-03-312014-12-312014-09-302014-06-302014-03-312013-12-312013-09-302013-06-302013-03-312012-12-312012-09-302012-06-302012-03-312011-12-312011-09-302011-06-302011-03-312010-12-312009-12-31
Value74747473737372727272727273737373737373737268686766640636262873626262626159586060
Percentage of TreasuryStockShares100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.00.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0100.0

Line plots across dimensions of each concept

us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementBusinessSegments


us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:StatementGeographical


us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:TimingOfTransferOfGoodOrService


us-gaap:RevenueFromContractWithCustomerExcludingAssessedTax us-gaap:ProductOrService


us-gaap:Revenues us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments


us-gaap:OperatingIncomeLoss us-gaap:ConsolidationItems


us-gaap:OperatingIncomeLoss us-gaap:ConsolidationItems, us-gaap:StatementBusinessSegments


us-gaap:StockholdersEquity us-gaap:StatementEquityComponents


us-gaap:Goodwill us-gaap:StatementBusinessSegments


us-gaap:FiniteLivedIntangibleAssetsNet us-gaap:FiniteLivedIntangibleAssetsByMajorClass


us-gaap:StockholdersEquity us-gaap:StatementEquityComponents