Product Warranty Reserves (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014	Jun. 29, 2013
Product Warranties Disclosures [Abstract]
Product warranty reserve at beginning of period	$ 2,001	$ 1,289	$ 1,850	$ 1,297
Warranty reserve assumed in business combination	0	0	209	0
Warranty liabilities accrued	1,178	1,054	2,192	1,954
Warranty liabilities settled	(1,241)	(947)	(2,449)	(1,777)
Changes for pre-existing warranty liabilities	272	170	408	92
Product warranty reserve at end of period	$ 2,210	$ 1,566	$ 2,210	$ 1,566