Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Rebates accrued	$ 27.5		$ 27.5		$ 24.2
Consignment inventory	18.2		18.2		$ 18.3
Revenue by product line and product type	736.8	$ 718.3	2,238.9	$ 2,023.3
Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	240.8	226.2	729.4	671.2
OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	349.1	350.9	1,049.8	944.3
EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	104.8	98.1	314.6	274.4
South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	34.5	38.3	122.2	114.8
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	7.6	6.5	22.9	22.3
Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	(1.7)	0.0	(3.7)
SmartSide Strand siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	191.1	163.2	563.4	492.6
SmartSide Strand siding [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	187.7	161.6	546.3	482.0
SmartSide Strand siding [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
SmartSide Strand siding [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
SmartSide Strand siding [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	3.4	3.3	17.1	14.1
SmartSide Strand siding [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
SmartSide Strand siding [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	(1.7)	0.0	(3.5)
SmartSide Fiber siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	30.4	28.4	84.2	86.4
SmartSide Fiber siding [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	30.4	28.4	84.2	86.4
SmartSide Fiber siding [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
SmartSide Fiber siding [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
SmartSide Fiber siding [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
SmartSide Fiber siding [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
SmartSide Fiber siding [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
CanExel siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	7.0	13.1	33.4	41.6
CanExel siding [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	7.0	13.1	33.4	41.6
CanExel siding [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
CanExel siding [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
CanExel siding [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
CanExel siding [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
CanExel siding [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
OSB - commodity [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	210.8	231.5	651.9	612.0
OSB - commodity [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	13.3	20.2	34.4	53.6
OSB - commodity [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	196.5	209.5	608.5	551.5
OSB - commodity [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	1.0	1.8	9.0	6.9
OSB - commodity [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
OSB - commodity [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
OSB - commodity [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
OSB - value-add [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	185.2	176.5	571.3	492.0
OSB - value-add [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.4	0.0	22.0	0.0
OSB - value-add [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	150.9	139.1	435.4	384.3
OSB - value-add [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	3.5	3.4	11.4	9.9
OSB - value-add [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	30.4	34.0	102.5	97.8
OSB - value-add [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
OSB - value-add [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LVL [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	35.7	37.7	112.7	107.9
LVL [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LVL [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LVL [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	35.7	37.7	112.7	107.9
LVL [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LVL [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LVL [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LSL [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	18.1	12.5	48.8	35.1
LSL [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LSL [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LSL [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	18.1	12.5	48.8	35.1
LSL [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LSL [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
LSL [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
I Joist [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	34.1	32.0	97.7	88.1
I Joist [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
I Joist [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
I Joist [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	34.1	32.0	97.7	88.1
I Joist [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
I Joist [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
I Joist [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Plywood [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	7.7	8.2	23.3	18.8
Plywood [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Plywood [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Plywood [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	7.7	8.2	23.3	18.8
Plywood [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Plywood [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Plywood [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	16.7	15.2	52.2	48.8
Other [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	2.0	2.9	9.1	7.6
Other [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	1.7	2.3	5.9	8.5
Other [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	4.7	2.5	11.7	7.7
Other [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.7	1.0	2.6	2.9
Other [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	7.6	6.5	22.9	22.3
Other [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	(0.2)
Commodity [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	218.5	239.7	675.2	630.8
Commodity [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	13.3	20.2	34.4	53.6
Commodity [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	196.5	209.5	608.5	551.5
Commodity [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	8.7	10.0	32.3	25.7
Commodity [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Commodity [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Commodity [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Value-add [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	501.6	463.4	1,511.5	1,343.7
Value-add [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	225.5	203.1	685.9	610.0
Value-add [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	150.9	139.1	435.4	384.3
Value-add [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	91.4	85.6	270.6	241.0
Value-add [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	33.8	37.3	119.6	111.9
Value-add [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	0.0	0.0	0.0
Value-add [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.0	(1.7)	0.0	(3.5)
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	16.7	15.2	52.2	48.8
Other [Member] | Siding [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	2.0	2.9	9.1	7.6
Other [Member] | OSB [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	1.7	2.3	5.9	8.5
Other [Member] | EWP [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	4.7	2.5	11.7	7.7
Other [Member] | South America [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	0.7	1.0	2.6	2.9
Other [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	7.6	6.5	22.9	22.3
Other [Member] | Intersegment [Member]
Disaggregation of Revenue [Line Items]
Revenue by product line and product type	$ 0.0	$ 0.0	$ 0.0	$ (0.2)