Commitments and Contingencies Warranty Liabilities (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013
Warranty Liabilities [Abstract]
Limited warranty period (in years)	25 years
Customer participation term (in years)	23 years
Warranty Liabilities [Roll Forward]
Balance at beginning of year	$ 4,153	$ 4,858
Additions charged to costs and expenses for current-year sales	3,237	2,113
Deductions from reserves	(3,231)	(2,568)
Changes in liability for pre-existing warranties during the current year, including expirations	274	(117)
Acquired warranty reserve(1)	0	658	[1]
Balance at end of period	$ 4,433	$ 4,944

[1] Acquired warranty reserve resulted from the acquisition of Comfortaire Corporation in the first quarter of fiscal 2013.