Commitments and Contingencies Warranty Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Oct. 01, 2016	Oct. 03, 2015
Warranty Liabilities [Roll Forward]
Balance at beginning of year	$ 10,028	$ 5,824
Additions charged to costs and expenses for current-year sales	7,014	7,514
Deductions from reserves	(7,976)	(4,995)
Changes in liability for pre-existing warranties during the current year, including expirations	(976)	1,426
Balance at end of period	$ 8,090	$ 9,769