Lease Obligations (Lease Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Amortization of right-of-use assets	$ 2.9	$ 3.6
Interest on lease liabilities	0.2	0.4
Operating lease cost	28.4	32.6
Short-term lease cost	0.0	0.3
Sublease income	(2.0)	(2.5)
Total lease cost	29.5	34.4
Operating cash flows from finance leases	0.0	0.0
Operating cash flows from operating leases	27.9	33.4
Financing cash flows from finance leases	3.0	7.4
Financing cash flows from finance leases, excluding discontinued operations		6.6
Right-of-use assets obtained in exchange for new finance lease liabilities	1.4	1.4
Right-of-use assets obtained in exchange for new operating lease liabilities		15.0
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 74.6	$ 15.0
Weighted-average remaining lease term — finance leases (years)	2 years 3 months 18 days	2 years
Weighted-average remaining lease term — operating leases (years)	5 years 8 months 12 days	4 years
Weighted-average discount rate — finance leases (percent)	4.50%	5.00%
Weighted-average discount rate — operating leases (percent)	5.40%	6.30%