Derivative Instruments - Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 20,121	$ 16,092	$ 3,601
Derivative liability, fair value	6,183	2,910	23,538
Derivatives designated as hedging instruments:
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	19,744	13,735	2,177
Derivative liability, fair value	1,191	1,139	18,875
Derivatives designated as hedging instruments: | Foreign currency forward exchange contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	16,703	12,122	1,787
Derivatives designated as hedging instruments: | Foreign currency forward exchange contracts | Other noncurrent assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	3,041	1,613	390
Derivatives designated as hedging instruments: | Foreign currency forward exchange contracts | Accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	1,045	954	17,456
Derivatives designated as hedging instruments: | Foreign currency forward exchange contracts | Other noncurrent liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	146	185	1,419
Derivatives not designated as hedging instruments: | Foreign currency forward exchange contracts | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	377	2,357	1,424
Derivatives not designated as hedging instruments: | Foreign currency forward exchange contracts | Accrued liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	$ 4,992	$ 1,771	$ 4,663