Acquisition (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended						9 Months Ended		21 Months Ended
	Oct. 20, 2015 USD ($)	Sep. 27, 2015 USD ($) $ / shares	Jun. 28, 2015 USD ($)	Mar. 29, 2015 USD ($)	Dec. 28, 2014 USD ($)	Sep. 28, 2014 USD ($) $ / shares	Jun. 29, 2014 USD ($)	Sep. 27, 2015 USD ($) $ / shares	Sep. 28, 2014 USD ($) $ / shares	Sep. 27, 2015 USD ($)
Business Acquisition [Line Items]
Number of Restaurants Acquired								9
Business acquisitions, purchase price								$ 1,657	$ 13,021
Proceeds from sale-leaseback transactions								3,136	6,604
Restaurant sales		$ 217,676				$ 179,822		629,948	499,858
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 Acquisition, Effective Date of Acquisition			Mar. 31, 2015
Business acquisitions, purchase price			$ 794
August 4, 2015 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired		5
Business Acquisition, Effective Date of Acquisition		Aug. 04, 2015
Business acquisitions, purchase price		$ 663
2014 and 2015 Acquisitions [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired										132
Business acquisitions, purchase price										$ 53,657
Properties sold in sale-leaseback transactions		1			10
Proceeds from sale-leaseback transactions				$ 1,123	$ 12,961
Restaurant sales		$ 39,400				7,800		110,800	8,600
Business Acquisition, Pro Forma Revenue		218,154				209,996		634,061	600,197
Business Acquisition, Pro Forma Net Income (Loss)		$ 7,319				$ (814)		$ (6,669)	$ (8,011)
Business Acquisition, Pro Forma Earnings Per Share, Basic and Diluted | $ / shares		$ 0.16				$ (0.02)		$ (0.19)	$ (0.27)
Subsequent Event [Member] | October 1, 2015 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired	5
Business acquisitions, purchase price	$ 5,000
Business acquisitions, properties purchased	1
Subsequent Event [Member] | October 20, 2015 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired	1
Business acquisitions, purchase price	$ 700