Product Warranty Reserves (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Product Warranties Disclosures [Abstract]
Product warranty reserve at beginning of period	$ 2,210	$ 1,566	$ 1,850	$ 1,297
Warranty reserve assumed in business combination	0	0	209	0
Warranty liabilities accrued	1,180	1,225	3,372	3,179
Warranty liabilities settled	(1,266)	(1,111)	(3,715)	(2,888)
Changes for pre-existing warranty liabilities	204	40	612	132
Product warranty reserve at end of period	$ 2,328	$ 1,720	$ 2,328	$ 1,720