Restructuring and Other Expense (Income) - Additional Information (Detail) - USD ($)				1 Months Ended		3 Months Ended		12 Months Ended
	May. 24, 2015	Dec. 10, 2013	Nov. 12, 2013	Jun. 30, 2013	Oct. 31, 2012	May. 31, 2014	May. 31, 2013	May. 31, 2015	May. 31, 2014
Restructuring Cost and Reserve [Line Items]
Amount of goodwill included in loss on sale of business								$ 1,891,000
Accrued severance cost	$ 2,221,000
Gain/loss on sale of assets								2,338,000	$ (10,589,000)
Aluminum High Pressure Cylinder Business
Restructuring Cost and Reserve [Line Items]
Cash proceeds from sale of business								8,415,000
Gain (loss) on sale of business								(2,670,000)
Amount of goodwill included in loss on sale of business								1,891,000
Accrued severance cost								664,000
ACT Business
Restructuring Cost and Reserve [Line Items]
Cash proceeds from sale of business								2,622,000
Gain (loss) on sale of business								332,000
Military Construction Business
Restructuring Cost and Reserve [Line Items]
Accrued severance cost								366,000
Midrise Construction Business
Restructuring Cost and Reserve [Line Items]
Accrued severance cost						$ 564,000
Baltimore Steel Facility
Restructuring Cost and Reserve [Line Items]
Accrued severance cost		$ 1,380,000
ITS
Restructuring Cost and Reserve [Line Items]
Gain/loss on sale of assets				$ 4,762,000
Cash proceeds from sale of assets				$ 7,457,000
Metal Framing
Restructuring Cost and Reserve [Line Items]
Facility exit and other costs incurred								413,000	924,000
Gain/loss on sale of assets									(112,000)
Pressure Cylinders
Restructuring Cost and Reserve [Line Items]
Facility exit and other costs incurred								853,000	377,000
Amount of goodwill included in loss on sale of business								$ 1,891,000
Accrued severance cost							$ 2,488,000		578,000
Gain/loss on sale of assets					$ 50,000
Pressure Cylinders | North America
Restructuring Cost and Reserve [Line Items]
Facility exit and other costs incurred			$ 524,000
Accrued severance cost			3,714,000
Gain/loss on sale of assets			$ 5,939,000
Commercial Stairs
Restructuring Cost and Reserve [Line Items]
Facility exit and other costs incurred									$ 652,000