Basis of Presentation and Summary of Significant Accounting Policies - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	$ 999,475	$ 2,945,758
Waters 401(k) Restoration Plan assets	33,104	35,645
Total	1,034,175	2,981,969
Contingent consideration	2,476	3,247
Total	2,700	3,429
Foreign Currency Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, derivative asset	503	566
Foreign currency exchange contracts	224	182
Cross Currency Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, derivative asset	1,093
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	164,315	591,988
Foreign Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	3,463	6,952
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	723,059	1,975,160
Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	108,638	371,511
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities		147
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Waters 401(k) Restoration Plan assets	33,104	35,645
Total	33,104	35,645
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	1,001,071	2,946,324
Total	224	182
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member] \| Foreign Currency Exchange Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, derivative asset	503	566
Foreign currency exchange contracts	224	182
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member] \| Cross Currency Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value, derivative asset	1,093
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member] \| US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	164,315	591,988
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member] \| Foreign Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	3,463	6,952
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member] \| Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	723,059	1,975,160
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member] \| Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities	108,638	371,511
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 2) [Member] \| Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale securities		147
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration	2,476	3,247
Total	$ 2,476	$ 3,247

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