Acquisitions and Divestitures - Acquisitions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 25, 2016 USD ($) restaurant	Dec. 27, 2015 USD ($) restaurant
Purchase price
Cash payment	$ 21	$ 13,352	$ 922
Fair value allocation of purchase price
Goodwill	$ 86,892	$ 85,529	$ 79,657
Multiple restaurants acquired
Acquisition disclosures
Number of restaurants acquired | restaurant		25	7
Purchase price
Cash payment		$ 13,352	$ 922
Cancellation of accounts and notes receivable		406
Total purchase price		13,758	922
Fair value allocation of purchase price
Property and equipment		1,362	648
Franchise rights		2,092	113
Goodwill		10,166	152
Other		138	9
Total purchase price		$ 13,758	$ 922