Summary of Restructuring and Acquisition Related Expenses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013	Sep. 26, 2014	Sep. 27, 2013
Restructuring And Acquisition Related Costs [Line Items]
Restructuring charges	$ 233	$ 1,447	$ 73	$ 3,532
Total acquisition related charges	538	106	1,876	1,192
Total restructuring and acquisition related costs	771	1,553	1,949	4,724
2011 Restructuring
Restructuring And Acquisition Related Costs [Line Items]
Restructuring charges	233	(2)	139	1,320
2013 Restructuring
Restructuring And Acquisition Related Costs [Line Items]
Restructuring charges		1,449	(66)	2,205
GERMANY
Restructuring And Acquisition Related Costs [Line Items]
Restructuring charges				7
Acquisition Charges
Restructuring And Acquisition Related Costs [Line Items]
Total acquisition related charges	26	106	774	1,192
JADAK
Restructuring And Acquisition Related Costs [Line Items]
Total acquisition related charges			668
JADAK | Earn-out Agreement
Restructuring And Acquisition Related Costs [Line Items]
Total acquisition related charges	$ 512		$ 1,102