Leases - Lease Costs (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 25, 2019 USD ($)	Sep. 25, 2019 USD ($)
Lessee, Lease, Description [Line Items]
Amortization of right-of-use assets	$ 592	$ 2,473
Interest on lease liabilities	906	3,740
Sublease Income	(8,156)	(20,164)
Total lease costs	$ 3,293	$ 14,813
Finance leases, weighted-average remaining lease term (in years)	9 years 7 months 6 days	9 years 7 months 6 days
Operating leases weighted-average remaining lease term (in years)	10 years 9 months 18 days	10 years 9 months 18 days
Finance leases, weighted-average discount rate	23.50%	23.50%
Operating leases, weighted-average discount rate	6.10%	6.10%
Occupancy [Member]
Lessee, Lease, Description [Line Items]
Operating lease costs	$ 1,811	$ 6,824
Variable lease costs	1,324	4,992
Franchise [Member]
Lessee, Lease, Description [Line Items]
Operating lease costs	4,850	11,926
Variable lease costs	1,924	4,862
General and Administrative Expenses [Member]
Lessee, Lease, Description [Line Items]
Operating lease costs	27	80
Variable lease costs	15	25
Restructuring Charges and Exit Costs [Member]
Lessee, Lease, Description [Line Items]
Variable lease costs	$ 0	$ 55