Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018
Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	$ 28,216	$ 15,757	$ 10,733
Charged to costs and expenses		9,440	5,095
Additions		3,019
Deductions			(71)
Balance at End of Year		28,216	15,757
Reserve for uncollectible accounts receivable
Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	7,341	4,205	2,271
Charged to costs and expenses		3,216	7,242
Deductions		(80)	(5,308)
Balance at End of Year		7,341	4,205
Reserve for franchisee notes receivable
Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	3,572	3,369	1,047
Recovered from costs and expenses		(77)	(393)
Additions		280	2,715
Balance at End of Year		3,572	3,369
Valuation allowance on deferred tax assets
Movement in Valuation Allowances and Reserves
Balance at Beginning of Year	17,303	8,183	7,415
Charged to costs and expenses	1,313	6,301
Recovered from costs and expenses			(1,754)
Additions	4,356	2,819	2,522
Balance at End of Year	$ 22,972	$ 17,303	$ 8,183