Fair Value - Assets Measured at Fair Value on Non-Recurring Basis (Parenthetical) (Detail) - Long Lived Assets Held And Used - USD ($)	Feb. 28, 2022	May 31, 2021
Production Equipment | Twinsburg
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value of assets	$ 700,000
Alternative Fuel Cylinders Manufacturing Line Facility | Jefferson
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair market value of assets		$ 400,000