Impairment Of Long-Lived Assets And Other Lease Charges (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2021 USD ($)	Jun. 28, 2020 USD ($) restaurant	Jun. 28, 2021 USD ($)	Jun. 28, 2020 USD ($) restaurant
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment and other lease charges	$ 144	$ 2,941	$ 497	$ 5,822
Restructuring Charges		200	200	1,400
Asset impairment charges	$ 100	$ 2,700	300	$ 4,400
Underperforming Restaurants [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment charges, number of restaurants | restaurant		6		9
Previously Impaired
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment charges		$ 100	$ 300	$ 300
Initial Impairment Charge [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment and other lease charges		$ 2,600		$ 4,100