Accrued Warranty Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Changes in product warranty liability [Roll Forward]
Balance at beginning of period	$ 7.9	$ 7.1
Claims paid	(1.6)	(1.0)
Warranty expense, net	1.6	1.0
Balance at end of period	$ 7.9	$ 7.1