Acquisition (Details) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended	21 Months Ended
	Oct. 01, 2017 USD ($)	Jan. 01, 2017 USD ($)	Oct. 02, 2016 USD ($)	Oct. 01, 2017 USD ($)	Oct. 02, 2016 USD ($)	Jan. 01, 2017 USD ($)	Oct. 01, 2017 USD ($)
Business Acquisition [Line Items]
Right of First Refusal, Number of States	20			20			20
Number of Restaurants Acquired						56	116
Business acquisitions, purchase price				$ 36,556	$ 33,407	$ 48,088	$ 84,651
Business acquisitions, properties purchased						15	15
Proceeds from sale-leaseback transactions				4,257	29,394
Restaurant sales	$ 285,235		$ 238,870	804,565	702,757
February 23, 2016 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			12
Business acquisitions, purchase price			$ 7,127
May 25, 2016 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			6
Business acquisitions, purchase price			$ 12,080
Business acquisitions, properties purchased			5
July 14, 2016 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			4
Business acquisitions, purchase price			$ 5,445
Business acquisitions, properties purchased			3
August 23, 2016 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			7
Business acquisitions, purchase price			$ 8,755
Business acquisitions, properties purchased			6
October 4, 2016 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired		3
Business acquisitions, purchase price		$ 1,623
November 15, 2016 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired		17
Business acquisitions, purchase price		$ 7,251
December 1, 2016 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired		7
Business acquisitions, purchase price		$ 5,807
Business acquisitions, properties purchased		1
February 28, 2017 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired	43
Business acquisitions, purchase price	$ 20,373
June 6, 2017 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			17
Business acquisitions, purchase price			$ 16,190
2016 Acquisitions [Member]
Business Acquisition [Line Items]
Properties sold in sale-leaseback transactions						14
Proceeds from sale-leaseback transactions						$ 19,100
2017 Acquisitions [Member]
Business Acquisition [Line Items]
Tax deductible goodwill	6,500			6,500			$ 6,500
Acquired Restaurants [Member]
Business Acquisition [Line Items]
Restaurant sales	$ 40,200		$ 8,300	$ 95,300	$ 15,200