Financial Instruments Measured at Fair Value - Fair Value Hierarchy (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jul. 02, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 35,980	$ 41,178
Interest rate swaps	2,252	711
Foreign exchange contracts	2,139	(738)
Contingent consideration	(2,522)	(3,889)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	37,849	37,262
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	35,980	41,178
Interest rate swaps	0	0
Foreign exchange contracts	0	0
Contingent consideration	0	0
Total Fair Value Assets And Liabilities Measured On Recurring Basis	35,980	41,178
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Interest rate swaps	2,252	711
Foreign exchange contracts	2,139	(738)
Contingent consideration	0	0
Total Fair Value Assets And Liabilities Measured On Recurring Basis	4,391	(27)
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	0	0
Interest rate swaps	0	0
Foreign exchange contracts	0	0
Contingent consideration	(2,522)	(3,889)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	$ (2,522)	$ (3,889)