Selected Quarterly Financial and Earnings Data (Unaudited) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 03, 2016 USD ($)	Sep. 27, 2015 USD ($)	Jun. 28, 2015 USD ($)	Mar. 29, 2015 USD ($)	Dec. 28, 2014 USD ($)	Sep. 28, 2014 USD ($)	Jun. 29, 2014 USD ($)	Mar. 30, 2014 USD ($)	Jan. 03, 2016 USD ($)	Dec. 28, 2014 USD ($)	Dec. 29, 2013 USD ($)
Quarterly Financial Information Disclosure [Abstract]
Restaurants Acquired	46	5	4		94	25	4		55	123
Acquisition-related costs	$ 800	$ 100		$ 200	$ 1,200	$ 400	$ 200	$ 100
Impairment and other lease charges	$ 300	$ 400	$ 700	$ 1,600	$ 1,700	$ 800	$ 400	$ 600	$ 3,078	$ 3,541	$ 4,462
Income tax expense, valuation allowance									2,959	24,326	624
Closed restaurants				15
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount									$ (2,959)	$ (24,326)	$ (624)
Weeks In fiscal period	14								53	52	52