Restructuring and Other Expense (Income), Net - Additional Information (Detail) $ in Thousands	12 Months Ended
	May 31, 2019 USD ($) Facility
Restructuring Cost and Reserve [Line Items]
Net gain on disposal of assets	$ 13,420
Other Non-significant Restructuring Activities
Restructuring Cost and Reserve [Line Items]
Severance expense	205
Facility exit costs reduction	10
Pressure Cylinders
Restructuring Cost and Reserve [Line Items]
Severance expense	89
Net gain on disposal of assets	11,458
Net proceeds from sale of business	27,577
Pressure Cylinders | Oil & gas equipment
Restructuring Cost and Reserve [Line Items]
Net gain on disposal of assets	$ 1,962
Number of facilities sold | Facility	2
Net proceeds from sale of business	$ 20,256
Pressure Cylinders | AMTROL
Restructuring Cost and Reserve [Line Items]
Severance expense	1,086
Facility exit costs	513
CNG Fuel Systems | North America
Restructuring Cost and Reserve [Line Items]
Severance expense	$ 519