Leases (Summary of Supplemental Cash Flow Information Related to Leases) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases		$ 6.3	$ 5.4	$ 6.8
Operating cash flows from finance leases		0.7	0.6
Payments for finance leases		2.1	1.8	0.0
ROU assets obtained in exchange for lease liabilities
Operating leases	[1]	7.3	5.4	$ 41.6
Finance leases		$ 0.3	$ 2.6

[1] The years ended December 31, 2021 and 2020 include increases in ROU assets of $3.2 million and $0.4 million, respectively, resulting from modifications that did not involve obtaining a new ROU asset. Modifications resulted from changes in the terms of existing leases.