Common Stock and Series B Convertible Preferred Stock - Share Repurchase Program (Details) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	3 Months Ended		6 Months Ended		8 Months Ended
	Jun. 03, 2021	May 11, 2021	Aug. 05, 2021	Jun. 27, 2021	Jun. 28, 2020	Jun. 27, 2021	Jun. 28, 2020	Jun. 27, 2021	Dec. 27, 2020	Nov. 04, 2020
Share repurchase program
Net (loss) income attributable to common shareholders				$ (79,898)	$ 15,707	$ (49,542)	$ 20,933
Series B Convertible Preferred Stock, par value				$ 0.01		$ 0.01		$ 0.01	$ 0.01
Dividends on redemption of Series B Convertible Preferred Stock				$ 109,852		$ 109,852
Preferred stock shares outstanding				0		0		0	0
Outstanding shares of common stock , net of repurchased stock				36,200,000		36,200,000		36,200,000	32,500,000
Series B Preferred Stock
Share repurchase program
Preferred stock shares outstanding				0		0		0	252,530
Starboard share repurchase agreement
Share repurchase program
Series B preferred stock converted into common stock (in shares)		171,613
Number of shares sold		3,458,360
Series B Preferred stock repurchased during period (in shares)		78,387
Series B Convertible Preferred Stock, par value		$ 0.01
Franchisee Investors repurchase program
Share repurchase program
Series B preferred stock converted into common stock (in shares)	1,530
Number of shares sold	30,769
Franchisee Investors repurchase program | Series B Preferred Stock
Share repurchase program
Stock repurchased during period, shares	1,000
Starboard and Franchisee share repurchase program
Share repurchase program
Cash payment for repurchase and conversion process	$ 188,600
Dividends on redemption of Series B Convertible Preferred Stock						$ 109,900
Per share dividends on redemption of Series B Convertible Preferred Stock				$ 3.15		$ 3.23
Common stock repurchase program
Share repurchase program
Stock repurchase program, authorized amount										$ 75,000
Stock repurchased during period, shares								116,000
Stock repurchased during period, value								$ 10,900
Share repurchased during period, average cost per share								$ 94.24
Common stock repurchase program | Subsequent event
Share repurchase program
Stock repurchased during period, shares			41,000
Stock repurchased during period, value			$ 4,300
Stock repurchase program, remaining authorized amount			$ 59,800