Leases Leases (Details)	12 Months Ended
	Dec. 25, 2019 USD ($) restaurant lease	Dec. 26, 2018 USD ($) restaurant	Dec. 27, 2017 USD ($)	Dec. 27, 2018 USD ($)
Lessee, Lease, Description [Line Items]
Operating Lease, Lease Income	$ 500,000	$ 517,000	$ 489,000
Capital Leases, Future Minimum Payments Due, Next Twelve Months	54,000	95,000
Operating Lease, Payments	26,450,000
Finance Lease, Principal Payments	(68,000)
Finance Lease, Right-of-Use Asset, Amortization	9,000
Operating Lease, Right-of-Use Asset	192,395,000	$ 0		$ 205,223,000
Operating Lease, Liability	$ 213,898,000			222,283,000
Number Of Finance Leases	1
Number of Restaurants with lease modification	11
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 10,595,000
Operating Lease, Impairment Loss	(4,731,000)
Impairment of Right-of-Use Assets	$ 3,220,000
Number of Restaurants Sold | restaurant	4
Number Of Restaurant Closed | restaurant	1	7
Finance Lease, Interest Expense	$ 27,000
Operating Lease, Cost	27,485,000
Short-term Lease, Cost	34,000
Variable Lease, Cost	641,000
Sublease Income	(2,430,000)
Lease, Cost	25,766,000
Operating Leases, Future Minimum Payments Due, Next Twelve Months	26,808,000	$ 25,388,000
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, Next Twelve Months	2,754,000	1,443,000
Capital Leases, Future Minimum Payments Due in Two Years	54,000	54,000
Operating Leases, Future Minimum Payments, Due in Two Years	25,978,000	24,437,000
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, within Two Years	2,887,000	1,108,000
Capital Leases, Future Minimum Payments Due in Three Years	45,000	54,000
Operating Leases, Future Minimum Payments, Due in Three Years	24,871,000	23,342,000
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, within Three Years	3,284,000	1,078,000
Capital Leases, Future Minimum Payments Due in Four Years	0	45,000
Operating Leases, Future Minimum Payments, Due in Four Years	22,309,000	22,338,000
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, within Four Years	3,318,000	1,001,000
Capital Leases, Future Minimum Payments Due in Five Years	0	0
Operating Leases, Future Minimum Payments, Due in Five Years	19,751,000	20,634,000
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, within Five Years	3,203,000	989,000
Capital Leases, Future Minimum Payments Due Thereafter	0	0
Operating Leases, Future Minimum Payments, Due Thereafter	139,454,000	150,342,000
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals, Thereafter	27,265,000	2,612,000
Capital Leases, Future Minimum Payments Due	153,000	248,000
Operating Leases, Future Minimum Payments Due	259,171,000	266,481,000
Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals	42,711,000	8,231,000
Capital Leases, Future Minimum Payments, Interest Included in Payments	36,000	64,000
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(45,273,000)
Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments	117,000	184,000
Current portion of obligations under finance leases	34,000	68,000
Operating Lease, Liability, Current	16,406,000	0
Obligations under finance leases, net of current portion	83,000	116,000
Obligations under operating leases, net of current portion	$ 197,492,000	$ 0
Lease Not Yet Commenced [Member]
Lessee, Lease, Description [Line Items]
Number Of Leases | lease	1
Property Lease [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Payments	$ 25,168,000
Finance Lease, Principal Payments	(68,000)
Finance Lease, Right-of-Use Asset, Amortization	9,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	10,339,000
Finance Lease, Interest Expense	27,000
Operating Lease, Cost	26,212,000
Short-term Lease, Cost	0
Variable Lease, Cost	455,000
Sublease Income	(2,430,000)
Lease, Cost	$ 24,273,000
Finance Lease, Weighted Average Remaining Lease Term	2 years 10 months
Operating Lease, Weighted Average Remaining Lease Term	12 years 1 month
Finance Lease, Weighted Average Discount Rate, Percent	11.10%
Operating Lease, Weighted Average Discount Rate, Percent	4.38%
Equipment Lease [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Payments	$ 1,282,000
Finance Lease, Principal Payments	0
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	256,000
Operating Lease, Impairment Loss	(157,000)
Operating Lease, Cost	1,273,000
Short-term Lease, Cost	34,000
Variable Lease, Cost	186,000
Sublease Income	0
Lease, Cost	$ 1,493,000
Operating Lease, Weighted Average Remaining Lease Term	3 years 2 months 12 days
Finance Lease, Weighted Average Discount Rate, Percent	0.00%
Operating Lease, Weighted Average Discount Rate, Percent	3.96%
Property lease modification [Member]
Lessee, Lease, Description [Line Items]
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	$ 4,700,000
Operating Lease, Impairment Loss	(4,574,000)
Restructuring Charges [Member]
Lessee, Lease, Description [Line Items]
Lease, Cost	727,000
Interest Expense [Member]
Lessee, Lease, Description [Line Items]
Lease, Cost	27,000
Depreciation and amortization [Member]
Lessee, Lease, Description [Line Items]
Lease, Cost	9,000
Operating Expense [Member]
Lessee, Lease, Description [Line Items]
Lease, Cost	24,540,000
General and Administrative Expense [Member]
Lessee, Lease, Description [Line Items]
Lease, Cost	$ 463,000
Accounting Standards Update 2016-02 [Member] | Property Lease [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset				200,555,000
Operating Lease, Liability				217,615,000
Accounting Standards Update 2016-02 [Member] | Equipment Lease [Member]
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset				4,668,000
Operating Lease, Liability				$ 4,668,000
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessor, Operating Lease, Term of Contract	20 years
Capital Leases of Lessee, Contingent Rentals, Basis Spread on Variable Rate	11.10%
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessor, Operating Lease, Term of Contract	3 years
Capital Leases of Lessee, Contingent Rentals, Basis Spread on Variable Rate	11.00%