Acquisition (Details) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended		21 Months Ended
	Aug. 20, 2019 USD ($)	Jun. 11, 2019 USD ($)	Apr. 30, 2019 USD ($) restaurant director $ / shares shares	Sep. 27, 2020 USD ($) shares	Sep. 29, 2019 USD ($) restaurant	Sep. 27, 2020 USD ($) shares	Sep. 29, 2019 USD ($)	Sep. 29, 2019 restaurant	Dec. 29, 2019 USD ($)
Business Acquisition [Line Items]
Business Acquisition, Pro Forma General And Administrative Expenses							$ 4,000
Right of First Refusal, Number of States				20		20
Number of Restaurants Acquired						234
Payments to Acquire Businesses, Gross						$ 275,979
Business acquisitions, purchase price						0	131,545
Proceeds from sale-leaseback transactions						20,342	7,018
Restaurant sales				$ 407,036	$ 402,345	1,126,972	$ 1,061,693
Goodwill				122,619		122,619			$ 122,619
April 30, 2019 Acquisition 2 [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired			220
Payments to Acquire Businesses, Gross			$ 259,083
June 11, 2019 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired		13
Payments to Acquire Businesses, Gross		$ 15,788
August 20, 2019 Acquisition [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired	1
Payments to Acquire Businesses, Gross	$ 1,108
Agreement And Plan Of Merger - Cambridge Holdings, LLC [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired | restaurant			132
Business acquisition, equity interest issued or issuable, number of shares | shares			7,400,000
Business Combination, Restrictions On Stock, Term Of Restrictions On Sale Or Transfer			2 years
Business Combination, Number Of Director Nominees That May Be Designated By Counterparty | director			2
Business Combination, Consideration Transferred			$ 259,100
Number of Restaurants Constructed | restaurant			33
Goodwill									84,060
Deferred income taxes									44,292
2019 Acquisition [Member]
Business Acquisition [Line Items]
Business Acquisition, Goodwill, Expected Tax Deductible Amount									$ 47,200
Goodwill				86		86
Deferred income taxes				29		29
Acquired Restaurants [Member]
Business Acquisition [Line Items]
Restaurant sales				$ 73,300		$ 210,600
Cambridge Holdings, LLC [Member] | Agreement And Plan Of Merger - Cambridge Holdings, LLC [Member]
Business Acquisition [Line Items]
Retirement of Outstanding Indebtedness			$ 113,800
Common Stock [Member]
Business Acquisition [Line Items]
Business Acquisition, Purchase Price, Conversion, Closing Price | $ / shares			$ 9.81
Common Stock [Member] | Agreement And Plan Of Merger - Cambridge Holdings, LLC [Member]
Business Acquisition [Line Items]
Business Combination, Consideration Transferred			$ 145,300
Burger King Corporate [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired | restaurant					165			179
Popeyes [Member]
Business Acquisition [Line Items]
Number of Restaurants Acquired | restaurant					55			55
Cambridge Holdings, LLC [Member] | Series C Preferred Stock [Member]
Business Acquisition [Line Items]
Issuance (in shares) | shares						10,000
Conversion of Stock, Shares Converted | shares				7,500,000