Goodwill (Details)	12 Months Ended
	Dec. 27, 2015 USD ($) restaurant item	Dec. 28, 2014 USD ($) restaurant item	Dec. 29, 2013 USD ($)
Goodwill
Goodwill, Beginning Balance	$ 82,007,000	$ 79,391,000
Acquisitions	135,000	3,661,000
Divestitures		(47,000)
Reclassification to assets held for sale	(1,690,000)
Foreign currency adjustments	(795,000)	(998,000)
Goodwill, Ending Balance	79,657,000	82,007,000	$ 79,391,000
Goodwill impairment loss	0	0	0
Domestic Company-owned Restaurants
Goodwill
Goodwill, Beginning Balance	62,228,000	58,567,000
Acquisitions	135,000	3,661,000
Goodwill, Ending Balance	$ 62,363,000	$ 62,228,000	58,567,000
Number of restaurants acquired | restaurant	7	13
Number of domestic markets in which acquired restaurants | item	3	4
International
Goodwill
Goodwill, Beginning Balance	$ 19,343,000	$ 20,388,000
Divestitures		(47,000)
Foreign currency adjustments	(795,000)	(998,000)
Goodwill, Ending Balance	16,858,000	19,343,000	20,388,000
Goodwill, accumulated impairment	2,300,000	$ 2,300,000	2,300,000
International | China Operations
Goodwill
Reclassification to assets held for sale	(1,690,000)
Number of Restaurants Sold | restaurant		4
All others
Goodwill
Goodwill, Beginning Balance	436,000	$ 436,000
Goodwill, Ending Balance	$ 436,000	$ 436,000	$ 436,000