Lease Arrangements (Lease Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finance lease expense
Amortization of right-of-use assets	$ 4.6	$ 3.7
Interest on lease liabilities	0.5	0.7
Operating lease expense	16.9	17.4
Other lease expense	6.4	6.3
Total lease expense	$ 28.4	$ 28.1