Financial Instruments Measured at Fair Value - Fair Value Hierarchy (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Sep. 27, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 37,193	$ 69,857
Interest rate swaps	(579)
Foreign exchange contracts	231	(654)
Contingent consideration	(10,779)	(5,845)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	26,066	63,358
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	37,193	69,857
Interest rate swaps	0
Foreign exchange contracts	0	0
Contingent consideration	0	0
Total Fair Value Assets And Liabilities Measured On Recurring Basis	37,193	69,857
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	(579)
Foreign exchange contracts	231	(654)
Contingent consideration	0	0
Total Fair Value Assets And Liabilities Measured On Recurring Basis	(348)	(654)
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
Foreign exchange contracts	0	0
Contingent consideration	(10,779)	(5,845)
Total Fair Value Assets And Liabilities Measured On Recurring Basis	$ (10,779)	$ (5,845)