Selected Segment Data (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Net sales:	$ 518.5	$ 567.0	$ 963.2	$ 1,098.1
Operating profit (loss):	(3.9)	88.7	(14.1)	177.2
Other operating credits and charges, net	(0.6)	(5.4)	(0.6)	(7.0)
Gain On Sale Or Impairment Of Long Lived Assets, Net	(0.5)	(0.7)	(0.5)	(0.7)
General corporate and other expenses, net	(20.7)	(21.3)	(48.0)	(43.9)
Business Combination, Acquisition Related Costs	0	35.9	0	35.9
Foreign currency gains (losses)	3.8	(3.6)	(0.5)	(4.3)
Investment income	1.7	3.1	3.5	6.6
Interest expense, net of capitalized interest	(7.4)	(9.8)	(15.1)	(20.4)
Income (loss) from continuing operations before taxes	(4.6)	118.4	(24.4)	206.3
Provision (benefit) for income taxes	(6.7)	24.3	(12.3)	47.2
Income (loss) from continuing operations	2.1	94.1	(12.1)	159.1
OSB [Member]
Segment Reporting Information [Line Items]
Net sales:	223.7	306.2	418.6	592.9
Operating profit (loss):	(5.5)	95.4	(7.4)	193.5
Siding [Member]
Segment Reporting Information [Line Items]
Net sales:	169.7	152.7	313.2	286.5
Operating profit (loss):	25.9	27.1	45.1	47.8
Engineered Wood Products [Member]
Segment Reporting Information [Line Items]
Net sales:	80.6	60.9	147.0	124.3
Operating profit (loss):	(5.0)	(5.1)	(8.1)	(8.6)
South America [Member]
Segment Reporting Information [Line Items]
Net sales:	41.9	44.3	78.5	89.4
Operating profit (loss):	4.0	6.3	8.2	12.5
Other [Member]
Segment Reporting Information [Line Items]
Net sales:	4.0	3.7	7.7	6.4
Operating profit (loss):	(1.3)	(2.2)	(2.0)	(3.8)
Intersegment elimination [Member]
Segment Reporting Information [Line Items]
Net sales:	(1.4)	(0.8)	(1.8)	(1.4)
Unconsolidated Affiliates [Member]
Segment Reporting Information [Line Items]
Other Operating Credits and Charges Associated with Unconsolidated Affiliates	0	(2.7)	0	(2.7)
Gain On Sale Or Impairment Of Long Lived Assets, Net	$ 0.5	$ 0.7	$ 0.5	$ 0.7