Restructuring and Other Expense - Additional Information (Detail) (USD $)	3 Months Ended
	Aug. 31, 2012
Restructuring Cost and Reserve [Line Items]
Facility exit and other costs incurred	$ 231,000
Gain on sale of assets held for sale	(1,158,000)
Employee severance cost	85,000
Metal Framing
Restructuring Cost and Reserve [Line Items]
Cash proceeds from sale of assets for sale assets	3,526,000
Gain on sale of assets held for sale	1,158,000
Commercial Stairs
Restructuring Cost and Reserve [Line Items]
Facility exit and other costs incurred	312,000
Early Retirement And Severance
Restructuring Cost and Reserve [Line Items]
Severance accrual adjustment	$ 235,000