Financial Instruments Measured at Fair Value - Fair Value Hierarchy (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Oct. 01, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	$ 3,525	$ 1,559
Available-for-sale securities	37,403	41,178
Interest rate swaps - asset	1,373	711
Foreign exchange contracts - asset	1,179	2,625
Foreign exchange contracts - liability	(2,047)	(3,363)
Contingent consideration	(4,197)	(3,889)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	(37,236)	(38,821)
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	3,525	1,559
Available-for-sale securities	37,403	41,178
Interest rate swaps - asset	0	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	(40,928)	(42,737)
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	0	0
Available-for-sale securities	0	0
Interest rate swaps - asset	1,373	711
Foreign exchange contracts - asset	1,179	2,625
Foreign exchange contracts - liability	(2,047)	(3,363)
Contingent consideration	0	0
Total Fair Value Assets And Liabilities Measured On Recurring Basis	(505)	27
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash Equivalents	0	0
Available-for-sale securities	0	0
Interest rate swaps - asset	0	0
Foreign exchange contracts - asset	0	0
Foreign exchange contracts - liability	0	0
Contingent consideration	(4,197)	(3,889)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	$ (4,197)	$ (3,889)