Acquisition (Details) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended		18 Months Ended
	Jun. 28, 2015 USD ($)	Dec. 28, 2014 USD ($)	Sep. 28, 2014 USD ($)	Jun. 29, 2014 USD ($) $ / shares	Jun. 28, 2015 USD ($) $ / shares	Jun. 29, 2014 USD ($) $ / shares	Jun. 28, 2015 USD ($)
Business Acquisition [Line Items]
Number of Restaurants Acquired							127
Business acquisitions, purchase price					$ 805	$ 681	$ 52,994
Properties sold in sale-leaseback transactions	1	10
Proceeds from sale-leaseback transactions					3,136	5,455
Restaurant sales	$ 219,102			$ 168,583	412,272	320,036
2014 Acquisitions [Member]
Business Acquisition [Line Items]
Proceeds from sale-leaseback transactions	1,123	$ 12,961
Restaurant sales	$ 38,800			800	71,400	800
Business Acquisition, Pro Forma Revenue				203,974	413,408	387,632
Business Acquisition, Pro Forma Net Income (Loss)				$ 175	$ (14,051)	$ (6,211)
Business Acquisition, Pro Forma Earnings Per Share, Basic and Diluted | $ / shares				$ 0.01	$ (0.40)	$ (0.23)
April 30, 2014 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired				4
Business Acquisition, Effective Date of Acquisition				Apr. 30, 2014
Business acquisitions, purchase price				$ 681
June 30, 2014 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			4
Business Acquisition, Effective Date of Acquisition			Jun. 30, 2014
Business acquisitions, purchase price			$ 3,819
Business acquisitions, properties purchased			1
July 22, 2014 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			21
Business Acquisition, Effective Date of Acquisition			Jul. 22, 2014
Business acquisitions, purchase price			$ 8,609
October 8, 2014 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired		30
Business Acquisition, Effective Date of Acquisition		Oct. 08, 2014
Business acquisitions, purchase price		$ 20,330
Business acquisitions, properties purchased		12
November 4, 2014 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired		64
Business Acquisition, Effective Date of Acquisition		Nov. 04, 2014
Business acquisitions, purchase price		$ 18,761
Restaurants to be remodeled		46
March 31, 2015 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired	4
Business acquisitions, purchase price	$ 794