Leases - Lease Obligations (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Leases [Abstract]
Finance leases - ROU assets	$ 57.6	$ 54.8
Finance leases - Accumulated depreciation	(17.5)	(15.0)
Operating leases - ROU assets	113.9	118.8
Operating leases - Accumulated depreciation	(32.1)	(28.7)
Total lease assets	121.9	129.9
Finance leases		(10.4)	$ (11.8)
Operating leases	(24.1)	(26.2)
Finance leases		(28.7)	$ (27.4)
Operating leases	(59.9)	(65.7)
Total lease liabilities	$ (123.2)	$ (131.0)