Financial Instruments Measured at Fair Value - Unobservable Inputs Reconciliation (Details) (Fair Value, Inputs, Level 3 [Member], Fair Value, Measurements, Recurring [Member], Contingent Consideration [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 28, 2014
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of December 31, 2013	$ (5,845)
Fair value of initial contingent consideration	(5,853)
Change in fair value of contingent consideration included in earnings	(1,051)
Foreign currency translation adjustment	51
Balance as of June 28, 2014	$ (12,698)