Income Taxes - Schedule of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 46.1	$ 45.2	$ 39.4
State	12.8	14.4	11.3
Total current	58.9	59.6	50.7
Deferred:
Federal	16.0	(3.7)	3.7
State	4.4	(1.0)	1.3
Total deferred	20.4	(4.7)	5.0
Total income tax expense	79.3	54.9	55.7
Operating Loss Carryforwards [Line Items]
Deficiency (benefit) of stock-based compensation plans	0.3	0.2	(0.5)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount	0.0	2.0	0.8
Federal tax credits	(0.2)	(4.3)	(4.3)
Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount	$ 2.0	$ 1.6	$ 0.0