Leases - Minimum Lease Commitments Under Prior Guidance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Operating leases
2019	$ 25.3		$ 21.7
2020	19.1		15.9
2021	13.7		9.9
2022	9.3		7.6
2023	7.3		5.4
Thereafter	18.4		10.9
Total	93.1		71.4
Minimum commitments for finance leases under prior lease guidance
2019			0.5
2020	0.1		0.5
2021	0.1		0.4
2022			0.2
Total	0.2		$ 1.6
Operating lease rental expense	$ 25.1	$ 23.7