Goodwill and Long-Lived Assets - Additional Information (Detail) - USD ($)		3 Months Ended			9 Months Ended			12 Months Ended
		Feb. 28, 2022		Feb. 28, 2021	Feb. 28, 2022		Feb. 28, 2021	May 31, 2021
Impaired Long Lived Assets Held And Used [Line Items]
Goodwill		$ 407,318,000			$ 407,318,000			$ 351,056,000
Impairment of long-lived assets		3,076,000		$ 0	3,076,000		$ 13,739,000
Impairment of long-lived assets		3,076,000		0	3,076,000		13,739,000
Fair Value, Nonrecurring
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell		700,000			700,000			400,000
Fair Value, Nonrecurring | Fair Value, Inputs, Level 2
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell		700,000			700,000			400,000
Long Lived Assets Held for Sale | Fair Value, Nonrecurring
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell		700,000	[1]		700,000	[1]		400,000	[2]
Long Lived Assets Held for Sale | Fair Value, Nonrecurring | Fair Value, Inputs, Level 2
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell		700,000	[1]		700,000	[1]		400,000	[2]
Oil and Gas Properties | Long Lived Assets Held And Used | Fair Value, Nonrecurring
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long-lived assets							1,441,000
Fixed asset net book value				7,375,000			7,375,000
Intangible assets net book value							2,374,000
Oil and Gas Properties | Long Lived Assets Held And Used | Fair Value, Nonrecurring | Fair Value, Inputs, Level 2
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell				5,934,000			5,934,000
Other
Impaired Long Lived Assets Held And Used [Line Items]
Goodwill		0			0			0
Impairment of goodwill					198,290,000			$ 198,290,000
Impairment of long-lived assets	[3]						11,810,000
Twinsburg | Samuel Joint Ventures Facility
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long-lived assets							13,739,000,000
Twinsburg | Samuel Joint Ventures Facility | Production Equipment
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell		700,000			$ 700,000
Impairment of long-lived assets		$ 3,076,000
Cryogenics
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long-lived assets							3,662,000
Impairment of long-lived assets							4,333,000
Cryogenics | Long Lived Assets Held for Sale
Impaired Long Lived Assets Held And Used [Line Items]
Carrying value long-lived assets				13,526,000			13,526,000
Cryogenics | Long Lived Assets Held for Sale | Fair Value, Nonrecurring
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell				9,193,000			9,193,000
Jefferson
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long-lived assets							1,423,000
Jefferson | Long Lived Assets Held And Used
Impaired Long Lived Assets Held And Used [Line Items]
Carrying value long-lived assets				1,823,000			1,823,000
Jefferson | Long Lived Assets Held And Used | Fair Value, Nonrecurring
Impaired Long Lived Assets Held And Used [Line Items]
Fair market value of assets, less costs to sell				$ 400,000			400,000
Superior Tools
Impaired Long Lived Assets Held And Used [Line Items]
Impairment of long-lived assets							$ 506,000

[1] Comprised of production equipment at our Twinsburg, Ohio facility with an estimated fair market value of $700,000.  Refer to “NOTE F – Goodwill and Long-Lived Assets” for additional information.

[2] Comprised of our alternative fuel cylinders assets at the Jefferson, Ohio facility with an estimated fair market value of $400,000.  Refer to “NOTE F – Goodwill and Long-Lived Assets” for additional information.  

[3] Includes the noncontrolling interest portion of impairment and restructuring (charges) gains of $4,888 and $(255) for the nine months ended February 28, 2022 and 2021, respectively