Accrued Warranty (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 26, 2014	Sep. 27, 2013
Product Warranties Disclosures [Abstract]
Balance at beginning of the period	$ 3,315	$ 2,204
Provision charged to cost of sales	1,361	1,382
Acquisition related warranty accrual	90	998
Use of provision	(1,529)	(1,280)
Foreign currency exchange rate changes	(14)	1
Balance at end of period	$ 3,223	$ 3,305