Income Taxes - Significant Components (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 1.5	$ 8.7	$ 9.7
State and local	0.5	0.2	0.6
Foreign	6.4	5.9	(14.7)
Total current	8.4	14.8	(4.4)
Deferred:
Federal	3.8	(30.7)	14.0
State and local	1.5	(0.2)	(0.1)
Foreign	(0.3)	(0.5)	1.1
Total deferred	5.0	(31.4)	15.0
Income tax expense (benefit), net	$ 13.4	$ (16.6)	$ 10.6