Goodwill - Schedule of Changes In Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2025	Dec. 29, 2024	Dec. 31, 2023
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 248.6
Impairment loss	0.0	$ (7.1)
Goodwill, ending balance	249.6	248.6
Operating Segments
Goodwill [Roll Forward]
Goodwill, beginning balance	248.6	254.1	$ 254.0
Purchase price adjustment	(0.6)		0.1
Business acquisition	1.6	2.8
Impairment loss		$ (7.1)
Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]		Closure and impairment charges
Disposition of assets		$ (1.2)
Goodwill, ending balance	249.6	248.6	254.1
Franchise Segment | Operating Segments
Goodwill [Roll Forward]
Goodwill, beginning balance	247.0	254.1	254.0
Purchase price adjustment	0.0		0.1
Business acquisition	0.0	0.0
Impairment loss		$ (7.1)
Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]		Closure and impairment charges
Disposition of assets		$ 0.0
Goodwill, ending balance	247.0	247.0	254.1
Company-Owned Restaurants | Operating Segments
Goodwill [Roll Forward]
Goodwill, beginning balance	1.6	0.0	0.0
Purchase price adjustment	(0.6)		0.0
Business acquisition	1.6	2.8
Impairment loss		$ 0.0
Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]		Closure and impairment charges
Disposition of assets		$ (1.2)
Goodwill, ending balance	$ 2.6	$ 1.6	$ 0.0