Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2016	Jun. 30, 2015	Jun. 28, 2016	Jun. 30, 2015	Dec. 29, 2015
Reconciliation unrecognized tax benefits
Income tax expense (benefit)	$ 274	$ (1,213)	$ (955)	$ (466)
Uncertain tax positions	$ 2,600		$ 2,600		$ 2,600