Accrued Product Warrenties Accrued Product Warrenties (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 30, 2012	Dec. 31, 2012	Mar. 31, 2012
Movement in Standard Product Warranty Accrual [Roll Forward]
Accrued product warranties, beginning of period	$ 16,152	$ 16,046		$ 15,994
Amounts paid for warranty services	(2,392)	(2,167)
Warranty provisions for products sold	2,706	1,835
Currency translation adjustments and other	186	280
Accrued product warranties, end of period	16,652			15,994
Current accrued product warranties, end of period	13,557		13,169	13,592
Long-term accrued product warranties, end of period	$ 3,095			$ 2,402