Segment Information (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014 Integer		Sep. 30, 2013
Segment Reporting Information [Line Items]
Number of Reportable Segments					3
Sales
Sales	$ 983,319,000		$ 877,979,000		$ 2,711,686,000		$ 2,475,152,000
Other Segment Information [Abstract]
Income (loss) before income taxes	50,418,000		25,462,000		100,148,000		62,400,000
Depreciation and amortization	13,203,000		8,962,000		38,005,000		26,205,000
EBITDA	69,100,000	[1]	39,500,000	[1]	154,500,000	[1]	103,200,000	[1]
Reconciliation from Segment Totals to Consolidated [Abstract]
Interest expense	(5,514,000)		(5,174,000)		(16,545,000)		(14,846,000)
Interest income	57,000		88,000		180,000		212,000
Income (loss) before income taxes	50,418,000		25,462,000		100,148,000		62,400,000
Wood Products [Member]
Sales
Sales	355,700,000		283,200,000		1,000,000,000		832,800,000
Other Segment Information [Abstract]
Income (loss) before income taxes	40,600,000		17,900,000		84,900,000		61,800,000
Depreciation and amortization	10,700,000		6,700,000		30,700,000		19,500,000
EBITDA	51,300,000	[1]	24,600,000	[1]	115,600,000	[1]	81,200,000	[1]
Reconciliation from Segment Totals to Consolidated [Abstract]
Income (loss) before income taxes	40,600,000		17,900,000		84,900,000		61,800,000
Building Materials Distribution [Member]
Sales
Sales	773,400,000		721,500,000		2,117,300,000		1,984,100,000
Other Segment Information [Abstract]
Income (loss) before income taxes	21,100,000		17,900,000		46,300,000		29,100,000
Depreciation and amortization	2,400,000		2,200,000		7,100,000		6,600,000
EBITDA	23,500,000	[1]	20,100,000	[1]	53,500,000	[1]	35,800,000	[1]
Reconciliation from Segment Totals to Consolidated [Abstract]
Income (loss) before income taxes	21,100,000		17,900,000		46,300,000		29,100,000
Corporate and Other [Member]
Sales
Sales	0		0		0		0
Other Segment Information [Abstract]
Income (loss) before income taxes	(5,800,000)		(5,200,000)		(14,700,000)		(13,900,000)
Depreciation and amortization	0		0		100,000		100,000
EBITDA	(5,800,000)	[1]	(5,200,000)	[1]	(14,600,000)	[1]	(13,800,000)	[1]
Reconciliation from Segment Totals to Consolidated [Abstract]
Income (loss) before income taxes	(5,800,000)		(5,200,000)		(14,700,000)		(13,900,000)
Intersegment Eliminations [Member]
Sales
Sales	(145,800,000)		(126,700,000)		(405,600,000)		(341,800,000)
Operating Segments [Member]
Sales
Sales	983,300,000		878,000,000		2,711,700,000		2,475,200,000
Other Segment Information [Abstract]
Income (loss) before income taxes	55,900,000		30,500,000		116,500,000		77,000,000
Reconciliation from Segment Totals to Consolidated [Abstract]
Income (loss) before income taxes	55,900,000		30,500,000		116,500,000		77,000,000
Operating Segments [Member] | Wood Products [Member]
Sales
Sales	210,000,000		156,500,000		594,500,000		491,100,000
Operating Segments [Member] | Building Materials Distribution [Member]
Sales
Sales	773,400,000		721,500,000		2,117,200,000		1,984,100,000
Operating Segments [Member] | Corporate and Other [Member]
Sales
Sales	0		0		0		0
Intersegment Eliminations [Member]
Sales
Sales	0		0		0		0
Intersegment Eliminations [Member] | Wood Products [Member]
Sales
Sales	145,800,000		126,700,000		405,500,000		341,800,000
Intersegment Eliminations [Member] | Building Materials Distribution [Member]
Sales
Sales	0		0		100,000		0
Intersegment Eliminations [Member] | Corporate and Other [Member]
Sales
Sales	0		0		0		0
Intersegment Eliminations [Member] | Intersegment Eliminations [Member]
Sales
Sales	$ (145,800,000)		$ (126,700,000)		$ (405,600,000)		$ (341,800,000)

[1] EBITDA is defined as income (loss) before interest (interest expense and interest income), income taxes, and depreciation and amortization. EBITDA is the primary measure used by our chief operating decision maker to evaluate segment operating performance and to decide how to allocate resources to segments. We believe EBITDA is useful to investors because it provides a means to evaluate the operating performance of our segments and our company on an ongoing basis using criteria that are used by our internal decision makers and because it is frequently used by investors and other interested parties when comparing companies in our industry that have different financing and capital structures and/or tax rates. We believe EBITDA is a meaningful measure because it presents a transparent view of our recurring operating performance and allows management to readily view operating trends, perform analytical comparisons, and identify strategies to improve operating performance. EBITDA, however, is not a measure of our liquidity or financial performance under generally accepted accounting principles (GAAP) and should not be considered as an alternative to net income (loss), income (loss) from operations, or any other performance measure derived in accordance with GAAP or as an alternative to cash flow from operating activities as a measure of our liquidity. The use of EBITDA instead of net income (loss) or segment income (loss) has limitations as an analytical tool, including the inability to determine profitability; the exclusion of interest expense, interest income, and associated significant cash requirements; and the exclusion of depreciation and amortization, which represent unavoidable operating costs. Management compensates for the limitations of EBITDA by relying on our GAAP results. Our measure of EBITDA is not necessarily comparable to other similarly titled captions of other companies due to potential inconsistencies in the methods of calculation.The following is a reconciliation of net income to EBITDA for the consolidated company: Three Months EndedSeptember 30 Nine Months EndedSeptember 30 2014 2013 2014 2013 (millions)Net income(1) $32.3 $15.9 $64.3 $107.1Interest expense 5.5 5.2 16.5 14.8Interest income (0.1) (0.1) (0.2) (0.2)Income tax provision (benefit)(1) 18.1 9.6 35.9 (44.7)Depreciation and amortization 13.2 9.0 38.0 26.2EBITDA $69.1 $39.5 $154.5 $103.2 _______________________________________ (1)The nine months ended September 30, 2013, includes a $68.7 million income tax benefit associated with the recording of net deferred tax assets upon our conversion to a corporation.