Basis of Presentation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Basis of Presentation
High end of the range of the required percentage voting interest held to account for investments with the equity method of accounting (as a percent)			50.00%
Service sales as a percentage of net sales			less than 1%
Number of reportable segments prior to the sale of Simpson Dura-Vent Company, Inc.			2
Number of reportable segments			3
Reconciliation of basic earnings per share ("EPS") to diluted EPS
Earnings from continuing operations, net of tax	$ 19,493	$ 21,059	$ 26,571		$ 30,889
Loss from discontinued operations, net of tax		(14,356)			(14,986)
Net income	$ 19,493	$ 6,703	$ 26,571	$ 12,683	$ 15,903
Basic weighted average shares outstanding (in shares)	49,404	49,417	49,753		49,403
Dilutive effect of potential common stock equivalents - stock options (in shares)	52	181	56		156
Diluted weighted average shares outstanding (in shares)	49,456	49,598	49,809		49,559
Net earnings (loss) per share - basic:
Continuing operations (in dollars per share)	$ 0.39	$ 0.43	$ 0.53		$ 0.63
Discontinued operations (in dollars per share)		$ (0.29)			$ (0.30)
Net income (in dollars per share)	$ 0.39	$ 0.14	$ 0.53		$ 0.32
Net earnings (loss) per share - diluted:
Continuing operations (in dollars per share)	$ 0.39	$ 0.42	$ 0.53		$ 0.62
Discontinued operations (in dollars per share)		$ (0.29)			$ (0.30)
Net income (in dollars per share)	$ 0.39	$ 0.14	$ 0.53		$ 0.32
Potentially dilutive securities excluded from earnings per diluted share because their effect is anti-dilutive (in shares)	1,743	646	1,743		856