Impairment of Long-Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	$ 1,603	$ 253	$ 1,809	$ 763
Company-operated restaurants
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	1,603	201	1,603	218
Restaurants leased or subleased to franchisees
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	0	0	165	0
Surplus Properties
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	$ 0	$ 52	$ 41	$ 545