Income Taxes - Reconciliation of Amount Computed by Applying the Federal Statutory Income Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Federal statutory tax on earnings before income taxes	$ 72.1	$ 1.7	$ 41.2
State income taxes, net of federal income tax benefit	15.8	(0.6)	8.0
Non-deductible officer's compensation	6.4	3.5	4.5
Valuation allowance - state and foreign net operating losses	1.8	1.1	0.0
Uncertain tax positions	0.1	1.7	(1.0)
Re-measurement of deferred taxes	(1.5)	1.9	8.3
Windfall deduction from equity compensation	(1.4)	(1.3)	(4.2)
Net operating loss carry back - CARES Act	0.0	(13.3)	0.0
Other	1.2	0.0	0.0
Income tax provision (benefit)	$ 94.5	$ (5.3)	$ 56.8