Impairment Of Long-Lived Assets And Other Lease Charges (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 29, 2019 USD ($)	Sep. 29, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jul. 01, 2018 USD ($)	Apr. 01, 2018 USD ($)	Dec. 29, 2019 USD ($)	Dec. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment and other lease charges	$ 1,800	$ 500	$ 400	$ 900	$ 300	$ 200	$ 2,900	$ 300	$ 3,564	$ 3,685	$ 2,827
Impairment charges									1,700	2,700	1,700
Sale Leaseback Transaction Current Period Loss Recognized										$ 800	$ 100
Sale Leaseback Losses, number of restaurants										4	1
Other lease charges									1,900	$ 200	$ 900
Other Adjustments, Liability For Closed Restaurants	$ 500								$ 500
Asset impairment charges, number of restaurants									7	6	5
Write Off Of Defective Product										$ 1,900
Previously Impaired [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges									$ 300	400	$ 700
Initial Impairments [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment charges									$ 1,300	$ 400	$ 1,100