Commitments and Contingencies Warranty Liabilities (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012
Warranty Liabilities [Abstract]
Limited Warranty Period (in years)	25
Customer participation term (in years)	23 years
Warranty Liabilities [Roll Forward]
Balance at beginning of year	$ 4,858	$ 6,310
Additions charged to costs and expenses for current-year sales	2,113	1,832
Deductions from reserves	(2,568)	(2,435)
Changes in liability for pre-existing warranties during the current year, including expirations	(117)	151
Acquired warranty reserve	658	0
Balance at end of period	$ 4,944	$ 5,858