Restructuring and Other Expense - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended				12 Months Ended			1 Months Ended		3 Months Ended		12 Months Ended						1 Months Ended	12 Months Ended		12 Months Ended		12 Months Ended			1 Months Ended		3 Months Ended
	Oct. 23, 2008 Person Facility	May 31, 2012	Feb. 28, 2010 Person	Nov. 30, 2009	Aug. 31, 2007 Person	May 31, 2012	May 31, 2011	May 31, 2010	Mar. 02, 2011 Metal Framing Facility	Feb. 28, 2009 Metal Framing Person	May 31, 2011 Metal Framing	Aug. 31, 2008 Metal Framing Person	May 31, 2011 Metal Framing	May 31, 2008 Metal Framing Person	May 31, 2012 Metal Framing	Dec. 31, 2008 Metal Framing Facility	Dec. 05, 2008 Metal Framing Facility	Sep. 25, 2007 Metal Framing Location	Dec. 05, 2008 Steel Processing Person	May 31, 2011 Steel Processing	Feb. 28, 2009 Steel Processing Facility	May 31, 2011 Steel Processing and Metal Framing	May 31, 2012 Vinyl Business	May 31, 2010 Metal Framing Facility	May 31, 2012 Early Retirement And Severance	May 31, 2012 ClarkDietrich	Mar. 02, 2011 ClarkDietrich Metal Framing Facility	Mar. 02, 2011 Joint Venture Transactions ClarkDietrich	May 31, 2011 Joint Venture Transactions ClarkDietrich
Restructuring Cost and Reserve [Line Items]
Number of individuals impacted by additional headcount reduction			113		63
Number Of location announced closure or downsizing																		5
Headcount reduction for restructuring plan	282									125		33		165					186
Number of facilities targeted to be closed	2																3
Number of facilities closed																1					1
Gains losses on sales of assets				$ 1,003,000
Impairment of long-lived assets						355,000	4,386,000	35,409,000			18,293,000													1,717,000				18,293,000	18,293,000
Restructuring and related expense																						3,726,000
Net gain on dispositions						8,285,000	1,073,000						245,000							828,000
Number of facilities									13																		6
Employee severance cost		1,143,000																											7,183,000
Facility exit and other costs incurred						9,116,000																							4,033,000
Severance accrual adjustment																									998,000
Cash proceeds from sale of assets for sale assets															14,005,000								6,125,000			10,948,000
Gain on sale of assets held for sale															5,417,000								766,000			2,102,000
Professional fees						$ 4,758,000