Commitments and Contingencies Warranty Liabilities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Warranty Liabilities [Abstract]
Limited Warranty Period (in years)	20
Customer participation term (in years)	18 years
Warranty Liabilities [Roll Forward]
Balance at beginning of year	$ 4,858	$ 6,310
Additions charged to costs and expenses for current-year sales	1,469	1,448
Deductions from reserves	(1,403)	(1,383)
Changes in liability for pre-existing warranties during the current year, including expirations	(306)	505
Acquired warranty reserve	658	0
Balance at end of period	$ 5,276	$ 6,880