Employee Pension Plans - Additional Information (Detail)	12 Months Ended
	May 31, 2021 USD ($) DefinedBenefitPlan	May 31, 2020 USD ($)	May 31, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Estimated net loss	$ 545,609
Description of investment policy and strategy for the defined benefit plan	The investment policy and strategy for the defined benefit plan is: (i) long-term in nature with liquidity requirements that are anticipated to be minimal due to the projected normal retirement date of the average employee and the current average age of participants;  (ii) to earn nominal returns, net of investment fees, equal to or in excess of the defined benefit plan’s liability growth rate; and (iii) to include a diversified asset allocation of domestic and international equities and fixed income investments.
Employer contribution to defined benifit plan in fiscal 2021	$ 142,000
Number of planned contributions in fiscal 2021 | DefinedBenefitPlan	11
Expected employer contribution to defined benefit plan during fiscal 2021	$ 1,558,000
Net periodic pension costs	$ (26,000)	$ 52,000	$ 53,000
Discount rate	2.65%	3.57%	4.02%
Austrian Pressure Cylinders
Defined Benefit Plan Disclosure [Line Items]
Accrued liability of unfunded plans included in other liabilities	$ 7,062,000	$ 6,863,000
Net periodic pension costs	$ 625,000	$ 494,000	$ 925,000
Assumed salary rate increase	2.75%	2.75%	2.75%
Discount rate	1.10%	1.65%	1.40%