Asset Disposals, Closure Costs and Restaurant Impairments (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($) restaurant	Jul. 01, 2014 USD ($)	Jun. 30, 2015 USD ($) restaurant	Jul. 01, 2014 USD ($)
Property, Plant and Equipment Impairment or Disposal [Abstract]
Restaurant impairments	$ 31	$ 0	$ 5,944	$ 5
Loss on disposal of assets	187	146	321	281
Closure costs and other	32	47	71	122
Total	$ 250	$ 193	$ 6,336	$ 408
Number of restaurants | restaurant	8		8