2.2.0.7 true Retirement Plans (Details) (USD $) 41100 - Disclosure - Retirement Plans (Details) true false false false 1 USD false false USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Pure Standard http://www.xbrl.org/2003/instance pure xbrli 0 EPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD true false false false U.S. Pension Plans us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 3 USD true false false false U.S. Pension Plans us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember 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USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 12 USD true false false false Non-U.S. Pension Plans us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ForeignPensionPlansDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 13 USD true false false false Non-U.S. Pension Plans us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_ForeignPensionPlansDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ 2 Retirement Plans [Abstract] 0 us-gaap_GeneralDiscussionOfPensionAndOtherPostretirementBenefitsAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 3 Estimated total employer contributions to defined benefit plans in current fiscal year, lower range 1 wat_EstimatedTotalEmployerContributionsToDefinedBenefitPlansInCurrentFiscalYearLowerRange wat false debit duration The lowest estimated amount of the employer's best estimate, as soon as it can be reasonably determined, of contributions... false false false false false false false false false false false false 1 true true false false 4000000 4000000 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false xbrli:monetaryItemType monetary The lowest estimated amount of the employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan during the current fiscal year. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions. No authoritative reference available. false 4 Estimated total employer contributions to defined benefit plans in current fiscal year, higher range 1 wat_EstimatedTotalEmployerContributionsToDefinedBenefitPlansInCurrentFiscalYearHigherRange wat false debit duration The highest estimated amount of the employer's best estimate, as soon as it can be reasonably determined, of contributions... false false false false false false false false false false false false 1 false true false false 5000000 5000000 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false xbrli:monetaryItemType monetary The highest estimated amount of the employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan during the current fiscal year. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions. No authoritative reference available. false 7 Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] 2 us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 8 Service cost 3 us-gaap_DefinedBenefitPlanServiceCost us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 12000 12000 true false false 3 false true false false 23000 23000 true false false 4 false true false false 42000 42000 true false false 5 false true false false 69000 69000 true false false 6 false true false false 118000 118000 true false false 7 false true false false 58000 58000 true false false 8 false true false false 310000 310000 true false false 9 false true false false 174000 174000 true false false 10 false true false false 424000 424000 true false false 11 false true false false 424000 424000 true false false 12 false true false false 1272000 1272000 true false false 13 false true false false 1272000 1272000 true false false xbrli:monetaryItemType monetary The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph a, h false 9 Interest cost 3 us-gaap_DefinedBenefitPlanInterestCost us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false true false false 1573000 1573000 true false false 3 false true false false 1544000 1544000 true false false 4 false true false false 4743000 4743000 true false false 5 false true false false 4632000 4632000 true false false 6 false true false false 75000 75000 true false false 7 false true false false 96000 96000 true false false 8 false true false false 281000 281000 true false false 9 false true false false 288000 288000 true false false 10 false true false false 256000 256000 true false false 11 false true false false 210000 210000 true false false 12 false true false false 768000 768000 true false false 13 false true false false 630000 630000 true false false xbrli:monetaryItemType monetary The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph a, h false 10 Expected return on plan assets 3 us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets us-gaap true credit duration No definition available. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false true false false -1777000 -1777000 true false false 3 false true false false -1678000 -1678000 true false false 4 false true false false -5347000 -5347000 true false false 5 false true false false -5034000 -5034000 true false false 6 false true false false -60000 -60000 true false false 7 false true false false -37000 -37000 true false false 8 false true false false -166000 -166000 true false false 9 false true false false -111000 -111000 true false false 10 false true false false -79000 -79000 true false false 11 false true false false -83000 -83000 true false false 12 false true false false -237000 -237000 true false false 13 false true false false -249000 -249000 true false false xbrli:monetaryItemType monetary An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 11 Net amortization: Prior service (credit) cost 3 us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0     true false false 3 false true false false 37000 37000 true false false 4 false false false false 0 0     true false false 5 false true false false 111000 111000 true false false 6 false true false false -14000 -14000 true false false 7 false true false false -14000 -14000 true false false 8 false true false false -40000 -40000 true false false 9 false true false false -42000 -42000 true false false 10 false false false false 0 0     true false false 11 false false false false 0 0     true false false 12 false false false false 0 0     true false false 13 false false false false 0 0     true false false xbrli:monetaryItemType monetary The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 12 Net amortization: Net actuarial loss (gain) 3 us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses us-gaap true credit duration No definition available. false false false false false false false false false false true negatedtotal false 1 false false false false 0 0 false false false 2 false true false false 286000 286000 true false false 3 false true false false 98000 98000 true false false 4 false true false false 810000 810000 true false false 5 false true false false 294000 294000 true false false 6 false false false false 0 0     true false false 7 false true false false 3000 3000 true false false 8 false false false false 0 0     true false false 9 false true false false 9000 9000 true false false 10 false true false false -13000 -13000 true false false 11 false true false false 12000 12000 true false false 12 false true false false -39000 -39000 true false false 13 false true false false 36000 36000 true false false xbrli:monetaryItemType monetary The amount of gains or losses recognized in net periodic benefit cost Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h true 13 Net periodic pension cost 4 us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false false false false 0 0 false false false 2 false true false false 94000 94000 true false false 3 false true false false 24000 24000 true false false 4 false true false false 248000 248000 true false false 5 false true false false 72000 72000 true false false 6 false true false false 119000 119000 true false false 7 false true false false 106000 106000 true false false 8 false true false false 385000 385000 true false false 9 false true false false 318000 318000 true false false 10 false true false false 588000 588000 true false false 11 false true false false 563000 563000 true false false 12 false true false false 1764000 1764000 true false false 13 false true false false 1689000 1689000 true false false xbrli:monetaryItemType monetary The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain or loss, prior service cost or credit, transition asset or obligation, and gain or loss due to settlements or curtailments). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h true 14 Defined benefit plan, contributions by employer 2 us-gaap_DefinedBenefitPlanContributionsByEmployer us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 true false false 3 false false false false 0 0 true false false 4 true true false false 4000000 4000000 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false xbrli:monetaryItemType monetary The amount of contributions made by the employer. 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