Impairment of Long-Lived Assets - Additional Information (Detail) $ in Thousands	3 Months Ended	6 Months Ended
	Nov. 30, 2015 USD ($)	Nov. 30, 2016 USD ($)	Nov. 30, 2015 USD ($) Facility
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets	$ 22,962	$ 0	$ 25,962
Engineered Cabs
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets			3,000
Pressure Cylinders
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets	$ 22,962		22,962
Pressure Cylinders | Oil and Gas Equipment Reporting Unit
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of long-lived assets			$ 22,962
Number of equipment facilities | Facility			2