Selected Segment Data (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Net sales:	$ 596.4	$ 464.9	$ 1,683.4	$ 1,429.6
Operating profit (loss):	76.9	(17.4)	148.0	(64.7)
Other operating credits and charges, net	0.0	(1.0)	(11.4)	(12.6)
Loss on sale or impairment of long-lived assets, net	(0.3)	(0.9)	(1.0)	(1.5)
General corporate and other expenses, net	(26.9)	(20.5)	(78.1)	(65.2)
Other non-operating items	(0.5)	(3.7)	1.4	(5.5)
Loss on early debt extinguishment	(13.2)	0.0	(13.2)	0.0
Investment income	2.5	0.5	6.4	2.9
Interest expense, net of capitalized interest	(9.0)	(8.4)	(26.3)	(23.1)
Income (loss) from continuing operations before taxes	58.1	(27.0)	120.7	(86.3)
Provision (benefit) for income taxes	(7.5)	(2.4)	13.1	(7.7)
Income (loss) from continuing operations	65.6	(24.6)	107.6	(78.6)
OSB [Member]
Segment Reporting Information [Line Items]
Net sales:	282.1	200.0	751.9	601.2
Operating profit (loss):	67.4	(11.1)	126.7	(57.6)
Siding [Member]
Segment Reporting Information [Line Items]
Net sales:	194.8	157.8	583.3	495.2
Operating profit (loss):	35.2	17.2	103.9	79.3
Engineered Wood Products [Member]
Segment Reporting Information [Line Items]
Net sales:	80.7	74.4	230.5	211.2
Operating profit (loss):	0.0	(0.9)	(2.0)	(7.3)
South America [Member]
Segment Reporting Information [Line Items]
Net sales:	31.7	26.8	103.2	101.4
Operating profit (loss):	3.3	2.4	15.3	6.8
Other [Member]
Segment Reporting Information [Line Items]
Net sales:	7.6	6.8	20.3	21.5
Operating profit (loss):	(0.4)	(0.6)	(1.0)	(2.5)
Intersegment elimination [Member]
Segment Reporting Information [Line Items]
Net sales:	$ (0.5)	$ (0.9)	$ (5.8)	$ (0.9)