Impairment Of Long-Lived Assets And Other Lease Charges (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 03, 2021 USD ($) restaurant	Sep. 27, 2020 USD ($) period restaurant	Oct. 03, 2021 USD ($) restaurant	Sep. 27, 2020 USD ($) restaurant period
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment and other lease charges	$ 784	$ 1,954	$ 1,281	$ 7,776
Restructuring Charges			400	2,400
Asset impairment charges	$ 600	$ 1,000	$ 900	$ 5,400
Underperforming Restaurants [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment charges, number of restaurants | restaurant	3	4	4	13
Asset impairment charges		$ 200
Asset Impairment Charges, Number of Restaurants Closed | period		3		12
Previously Impaired
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment charges			$ 400	$ 500
Initial Impairment Charge [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment and other lease charges	$ 500	$ 700	$ 500	$ 4,900
Capital Expenditures At Underperforming Restaurants [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment charges	100
Other Lease Charges [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment and other lease charges	$ 200	$ 1,000