1.0.0.3 false Consolidated Statements of Cash Flows (unaudited) (USD $) In Thousands false 1 $ false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 7 Cash flows from operating activities: 5 us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 8 Net income 6 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 219190000 219190 false false 2 true true 223126000 223126 false false No definition available. No authoritative reference available. false 10 Adjustments to reconcile net income to net cash provided by operating activities: 7 us-gaap_AdjustmentsNoncashItemsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 11 Provisions for doubtful accounts on accounts receivable 8 us-gaap_ProvisionForDoubtfulAccounts us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 844000 844 false false 2 false true 2671000 2671 false false No definition available. No authoritative reference available. false 12 Provisions on inventory 8 us-gaap_InventoryWriteDown us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 5577000 5577 false false 2 false true 7757000 7757 false false No definition available. No authoritative reference available. false 13 Stock-based compensation 8 us-gaap_ShareBasedCompensation us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 21757000 21757 false false 2 false true 23181000 23181 false false No definition available. No authoritative reference available. false 14 Deferred income taxes 8 us-gaap_DeferredIncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 1696000 1696 false false 2 false true -14313000 -14313 false false No definition available. No authoritative reference available. false 15 Depreciation 8 us-gaap_Depreciation us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 23782000 23782 false false 2 false true 22052000 22052 false false No definition available. No authoritative reference available. false 16 Amortization of intangibles 8 us-gaap_AmortizationOfIntangibleAssets us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 18790000 18790 false false 2 false true 30413000 30413 false false No definition available. No authoritative reference available. false 17 Change in operating assets and liabilities, net of acquisitions: 7 us-gaap_IncreaseDecreaseInOperatingCapitalAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 18 Decrease in accounts receivable 8 us-gaap_IncreaseDecreaseInAccountsReceivable us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 12070000 12070 false false 2 false true 28255000 28255 false false No definition available. No authoritative reference available. false 19 Increase in inventories 8 us-gaap_IncreaseDecreaseInInventories us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -18619000 -18619 false false 2 false true -42506000 -42506 false false No definition available. No authoritative reference available. false 20 Decrease in other current assets 8 us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 3652000 3652 false false 2 false true 3973000 3973 false false No definition available. No authoritative reference available. false 21 Increase in other assets 8 us-gaap_IncreaseDecreaseInOtherOperatingAssets us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -1584000 -1584 false false 2 false true -2275000 -2275 false false No definition available. No authoritative reference available. false 22 Increase in accounts payable and other current liabilities 8 us-gaap_IncreaseDecreaseInAccountsPayableAndAccruedLiabilities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 906000 906 false false 2 false true 459000 459 false false No definition available. No authoritative reference available. false 23 Increase in deferred revenue and customer advances 8 wat_IncreaseInDeferredRevenueAndCustomerAdvances wat false debit duration monetary Increase in deferred revenue and customer advances false false false false false false false false false 1 false true 14245000 14245 false false 2 false true 14135000 14135 false false Increase in deferred revenue and customer advances No authoritative reference available. false 24 (Decrease) increase in other liabilities 8 us-gaap_IncreaseDecreaseInOtherOperatingLiabilities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -3902000 -3902 false false 2 false true 9102000 9102 false false No definition available. No authoritative reference available. true 25 Net cash provided by operating activities 5 us-gaap_NetCashProvidedByUsedInOperatingActivities us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true 298404000 298404 false false 2 false true 306030000 306030 false false No definition available. No authoritative reference available. false 27 Cash flows from investing activities: 5 us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 28 Additions to property, plant, equipment and software capitalization 6 wat_AdditionsToPropertyPlantEquipmentAndSoftwareCapitalization wat false credit duration monetary Additions to property, plant, equipment and software capitalization false false false false false false false false false 1 false true -80399000 -80399 false false 2 false true -49078000 -49078 false false Additions to property, plant, equipment and software capitalization No authoritative reference available. false 29 Business acquisitions, net of cash acquired 6 us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -36086000 -36086 false false 2 false true -2982000 -2982 false false No definition available. No authoritative reference available. false 30 Purchase of short-term investments 6 us-gaap_PaymentsToAcquireShortTermInvestments us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -317342000 -317342 false false 2 false true -19738000 -19738 false false No definition available. No authoritative reference available. false 31 Maturity of short-term investments 6 us-gaap_ProceedsFromSaleOfShortTermInvestments us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 129611000 129611 false false 2 false true 115419000 115419 false false No definition available. No authoritative reference available. true 32 Net cash (used in) provided by investing activities 5 us-gaap_NetCashProvidedByUsedInInvestingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -304216000 -304216 false false 2 false true 43621000 43621 false false No definition available. No authoritative reference available. false 34 Cash flows from financing activities: 5 us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false No definition available. false 35 Proceeds from debt issuances 6 us-gaap_ProceedsFromIssuanceOfLongTermDebt us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 169024000 169024 false false 2 false true 468429000 468429 false false No definition available. No authoritative reference available. false 36 Payments on debt 6 us-gaap_RepaymentsOfLongTermDebt us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -64393000 -64393 false false 2 false true -325117000 -325117 false false No definition available. No authoritative reference available. false 37 Payments of debt issuance costs 6 us-gaap_PaymentsOfDebtIssuanceCosts us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true -501000 -501 false false No definition available. No authoritative reference available. false 38 Proceeds from stock plans 6 us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 8159000 8159 false false 2 false true 23122000 23122 false false No definition available. No authoritative reference available. false 39 Purchase of treasury shares 6 us-gaap_PaymentsForRepurchaseOfCommonStock us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true -157212000 -157212 false false 2 false true -211054000 -211054 false false No definition available. No authoritative reference available. false 40 Excess tax benefit related to stock option plans 6 us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 7787000 7787 false false No definition available. No authoritative reference available. false 41 Proceeds (payments) of debt swaps and other derivative contracts 6 wat_PaymentsOfDebtSwapsAndOtherDerivativeContracts wat false debit duration monetary Payments of debt swaps and other derivative contracts false false false false false false false false false 1 false true 4495000 4495 false false 2 false true -3706000 -3706 false false Payments of debt swaps and other derivative contracts No authoritative reference available. true 42 Net cash used in financing activities 5 us-gaap_NetCashProvidedByUsedInFinancingActivities us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true -39927000 -39927 false false 2 false true -41040000 -41040 false false No definition available. No authoritative reference available. false 43 Effect of exchange rate changes on cash and cash equivalents 4 us-gaap_EffectOfExchangeRateOnCashAndCashEquivalents us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 7634000 7634 false false 2 false true -13344000 -13344 false false No definition available. No authoritative reference available. true 44 (Decrease) increase in cash and cash equivalents 4 us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease us-gaap true na duration monetary No definition available. false false false false false false false false false 1 false true -38105000 -38105 false false 2 false true 295267000 295267 false false No definition available. No authoritative reference available. false 45 Cash and cash equivalents at beginning of period 3 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false true false false 1 false true 428522000 428522 false false 2 false true 597333000 597333 false false No definition available. No authoritative reference available. false 46 Cash and cash equivalents at end of period 3 us-gaap_CashAndCashEquivalentsAtCarryingValue us-gaap true debit instant monetary No definition available. false false false false false false false true false 1 true true 390417000 390417 false false 2 true true 892600000 892600 false false No definition available. No authoritative reference available. false false 2 37 false Thousands UnKnown UnKnown false true