Income Taxes (Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income tax provision at the statutory rate	$ 65.8	$ 50.7	$ 42.9
State income taxes, net of federal benefit	15.2	12.7	10.6
Permanent difference – non deductible items	3.3	1.3	1.4
Disallowed meals and entertainment expenses	0.2	0.5	1.3
Excess stock-based compensation benefit	(2.0)	(1.1)	(0.6)
Work opportunity tax credit	(3.1)	(2.0)	(2.5)
Other	2.2	1.8	1.6
Total	$ 81.6	$ 63.9	$ 54.7
U.S. federal statutory tax rate	21.00%	21.00%	21.00%