Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Loss contingency accrual	$ 10.8	$ 15.1
Current portion of contingency reserves	(2.3)	(3.4)
Long-term portion of contingency reserves	8.5	11.7
Reserve for Environmental Costs [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual, Period Increase (Decrease)	2.1	(1.2)	$ (0.7)
Loss contingency accrual	10.6	15.0	$ 15.9	$ 16.6
Hardboard Siding Reserves
Loss Contingencies [Line Items]
Loss contingency accrual	$ 0.2	$ 0.1