Goodwill (Details) $ in Thousands	12 Months Ended
	Dec. 30, 2018 USD ($) restaurant item	Dec. 31, 2017 USD ($)	Dec. 25, 2016 USD ($)
Goodwill
Goodwill, Beginning Balance	$ 86,892	$ 85,529
Divestitures	(1,359)
Foreign currency adjustments	(1,017)	1,363
Goodwill, Ending Balance	84,516	86,892
Goodwill impairment loss	0	0
Domestic Company-owned Restaurants
Goodwill
Goodwill, Beginning Balance	70,048	70,048
Divestitures	(1,359)
Goodwill, Ending Balance	$ 68,689	70,048
Number of restaurants divested | restaurant	62
Number of domestic markets in which restaurants divested | item	2
International
Goodwill
Goodwill, Beginning Balance	$ 16,408	15,045
Foreign currency adjustments	(1,017)	1,363
Goodwill, Ending Balance	15,391	16,408
Goodwill, accumulated impairment	2,300	2,300	$ 2,300
All others
Goodwill
Goodwill, Beginning Balance	436	436
Goodwill, Ending Balance	$ 436	$ 436