Income Taxes - Income Before Taxes and Tax Provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Domestic and foreign components of income before taxes:
Domestic	$ (14.0)	$ 18.4	$ 31.6
Foreign	211.8	159.2	96.4
Income before income taxes and noncontrolling interest in consolidated subsidiaries	197.8	177.6	128.0
Current income tax (benefit) expense:
Federal	32.2	(2.4)	5.7
State	2.0	0.3	1.3
Foreign	42.7	59.8	50.0
Total current income tax expense	76.9	57.7	57.0
Deferred income tax (benefit) expense:
Federal	35.5	3.1	(31.1)
State	(0.4)	(5.3)	(2.4)
Foreign	5.5	(32.4)	(0.4)
Total deferred income tax (benefit) expense	40.6	(34.6)	(33.9)
Income tax provision	$ 117.5	$ 23.1	$ 23.1