Financial Instruments - Fair Value of Outstanding Derivative Contracts Recorded as Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	$ 5,018	$ 5,878
Liability derivatives (Level 2)	4,783	8,491
Foreign currency exchange forward contracts | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	3,559	5,244
Foreign currency exchange forward contracts | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	2,934	7,123
Interest rate swaps | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	1,331	464
Interest rate swaps | Other assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	128	170
Interest rate swaps | Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	1,849	1,368
Fair Value of Derivatives Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	4,429	2,963
Liability derivatives (Level 2)	1,873	1,521
Fair Value of Derivatives Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	2,970	2,329
Fair Value of Derivatives Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	24	153
Fair Value of Derivatives Designated as Hedging Instruments | Interest rate swaps | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	1,331	464
Fair Value of Derivatives Designated as Hedging Instruments | Interest rate swaps | Other assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	128	170
Fair Value of Derivatives Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	1,849	1,368
Fair Value of Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	589	2,915
Liability derivatives (Level 2)	2,910	6,970
Fair Value of Derivatives Not Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	589	2,915
Fair Value of Derivatives Not Designated as Hedging Instruments | Foreign currency exchange forward contracts | Other current liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	2,910	6,970
Fair Value of Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other current assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	0	0
Fair Value of Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other assets
Derivatives, Fair Value [Line Items]
Asset derivatives (Level 2):	0	0
Fair Value of Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Other liabilities
Derivatives, Fair Value [Line Items]
Liability derivatives (Level 2)	$ 0	$ 0