Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2025	Dec. 29, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total revenues	$ 879.3	$ 812.3	$ 831.1
Gross profit	359.3	375.3	396.7
Stock based compensation (direct)	15.9	16.3	10.6
(Gain) loss on disposition of assets	(0.5)	(3.2)	2.4
Interest expense, net	78.0	72.1	70.0
Closure and impairment charges	40.0	9.2	3.6
Amortization of intangible assets	11.9	10.8	10.9
Loss on extinguishment of debt	0.9	0.0	0.0
Income before income taxes	25.2	89.5	111.7
Advertising revenues
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	281.8	290.4	300.8
Operating Segments
Segment Reporting Information [Line Items]
Total revenues	879.3	812.3	831.1
Interest expense from finance leases	2.7	2.9	2.8
Depreciation and amortization	13.3	11.0	11.4
Other segment items	222.2	132.7	119.4
Gross profit	359.3	375.3	396.7
Stock based compensation (direct)	3.6	5.7	2.5
(Gain) loss on disposition of assets	(0.5)	(3.2)	0.6
Other G&A expenses (direct and allocated)	132.9	119.3	126.9
Segment operating profit	223.3	253.5	266.7
Operating Segments | Advertising revenues
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	281.8	290.4	300.8
Operating Segments | Revenues excluding advertising revenue
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	597.5	521.9	530.3
Operating Segments | Franchise
Segment Reporting Information [Line Items]
Total revenues	665.5	686.0	706.4
Interest expense from finance leases	0.0	0.0	0.0
Depreciation and amortization	0.6	1.4	1.1
Other segment items	40.8	48.0	42.5
Gross profit	342.3	346.1	362.0
Stock based compensation (direct)	3.6	5.7	2.5
(Gain) loss on disposition of assets	(0.5)	0.0	0.0
Other G&A expenses (direct and allocated)	125.0	119.3	126.9
Segment operating profit	214.2	221.1	232.5
Operating Segments | Franchise | Advertising revenues
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	281.8	290.4	300.8
Operating Segments | Franchise | Revenues excluding advertising revenue
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	383.7	395.5	405.6
Operating Segments | Company-Owned Restaurants
Segment Reporting Information [Line Items]
Total revenues	104.6	9.3	2.1
Interest expense from finance leases	0.0	0.0	0.0
Depreciation and amortization	3.1	(0.6)	(0.2)
Other segment items	109.5	10.5	2.4
Gross profit	(8.1)	(0.6)	0.0
Stock based compensation (direct)	0.0	0.0	0.0
(Gain) loss on disposition of assets	0.0	(2.2)	0.2
Other G&A expenses (direct and allocated)	7.9	0.0	0.0
Segment operating profit	(16.0)	1.6	(0.2)
Operating Segments | Company-Owned Restaurants | Advertising revenues
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	0.0	0.0	0.0
Operating Segments | Company-Owned Restaurants | Revenues excluding advertising revenue
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	104.6	9.3	2.1
Operating Segments | Rental
Segment Reporting Information [Line Items]
Total revenues	109.3	117.1	122.6
Interest expense from finance leases	2.7	2.9	2.8
Depreciation and amortization	9.6	10.1	10.5
Other segment items	71.9	74.2	74.6
Gross profit	25.0	29.9	34.7
Stock based compensation (direct)	0.0	0.0	0.0
(Gain) loss on disposition of assets	0.0	(1.0)	0.3
Other G&A expenses (direct and allocated)	0.0	0.0	0.0
Segment operating profit	25.0	30.9	34.4
Operating Segments | Rental | Advertising revenues
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	0.0	0.0	0.0
Operating Segments | Rental | Revenues excluding advertising revenue
Segment Reporting Information [Line Items]
Revenues excluding advertising revenue	109.3	117.1	122.6
Segment Reporting Excluding Corporate Expenditure
Segment Reporting Information [Line Items]
Depreciation and amortization	17.5	17.4	13.3
Stock based compensation (direct)	9.6	10.2	9.5
(Gain) loss on disposition of assets			1.8
Other G&A expenses (direct and allocated)	40.2	44.2	45.8
Interest expense, net	78.0	72.1	70.0
Closure and impairment charges	40.0	9.2	3.6
Amortization of intangible assets	11.9	10.8	10.9
Loss on extinguishment of debt	0.9
Income before income taxes	$ 25.2	$ 89.5	$ 111.7