Summary of Significant Accounting Policies - Property and Equipment At Cost and Depreciable Useful Lives (Details) - USD ($) $ in Millions	Dec. 29, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property and equipment	$ 140.0	$ 138.1
Total property, plant and equipment, including held-for-sale, gross		165.9
Land
Property, Plant and Equipment [Line Items]
Property and equipment	0.0
Total property, plant and equipment, including held-for-sale, gross		0.0
Work in process
Property, Plant and Equipment [Line Items]
Property and equipment	2.3
Total property, plant and equipment, including held-for-sale, gross		6.7
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 0.4
Total property, plant and equipment, including held-for-sale, gross		0.4
Estimated useful life	30 years
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment	$ 119.9
Total property, plant and equipment, including held-for-sale, gross		123.1
Computer hardware and software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Computer hardware and software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	12 years
Equipment, furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	$ 10.9
Total property, plant and equipment, including held-for-sale, gross		22.6
Estimated useful life	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 6.5
Total property, plant and equipment, including held-for-sale, gross		$ 13.1
Leasehold improvements | Headquarters
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Leasehold improvements | Maximum | Branches
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years