Impairment of Long-Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	$ 198	$ 1,603	$ 1,684	$ 1,809
Surplus properties
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	112	0	1,397	41
Company-operated restaurants
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	86	1,603	287	1,603
Restaurants leased or subleased to franchisees
Impaired Long-Lived Assets Held and Used
Impairment of long-lived assets	$ 0	$ 0	$ 0	$ 165