Financial Instruments Measured at Fair Value (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2017		Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	$ 289,938	[1]	$ 2,660
Available-for-sale securities	52,683		37,915
Interest rate swaps - asset			152
Interest rate swaps - liability	(149)
Foreign exchange contracts - asset	5,499		4,685
Foreign exchange contracts - liability	(8,581)		(3,444)
Contingent consideration	(3,176)		(4,027)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	336,214		37,941
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	3,267		2,660
Available-for-sale securities	52,683		37,915
Interest rate swaps - asset			0
Interest rate swaps - liability	0
Foreign exchange contracts - asset	0		0
Foreign exchange contracts - liability	0		0
Contingent consideration	0		0
Total Fair Value Assets And Liabilities Measured On Recurring Basis	55,950		40,575
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	286,671	[1]	0
Available-for-sale securities	0		0
Interest rate swaps - asset			152
Interest rate swaps - liability	(149)
Foreign exchange contracts - asset	5,499		4,685
Foreign exchange contracts - liability	(8,581)		(3,444)
Contingent consideration	0		0
Total Fair Value Assets And Liabilities Measured On Recurring Basis	283,440		1,393
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents	0		0
Available-for-sale securities	0		0
Interest rate swaps - asset			0
Interest rate swaps - liability	0
Foreign exchange contracts - asset	0		0
Foreign exchange contracts - liability	0		0
Contingent consideration	(3,176)		(4,027)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	$ (3,176)		$ (4,027)

[1] Cash equivalents include $286,671 invested in certificates of deposit, with an original maturity of less than three months, held in anticipation of our acquisition of eInfochips, which closed in January 2018 (see Note 19).