Employee Pension Plans - Summary of Defined Benefit Plan's Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	May 31, 2021	May 31, 2020	May 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	$ 33,136	$ 28,510	$ 26,258
Quoted Prices In Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	33,136	28,510
Money Market Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	1,664	1,613
Money Market Funds | Quoted Prices In Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	1,664	1,613
Bond Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	12,629	12,619
Bond Funds | Quoted Prices In Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	12,629	12,619
Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	16,022	11,885
Equity Funds | Quoted Prices In Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	16,022	11,885
Administrative Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	2,821	2,393
Administrative Funds | Quoted Prices In Active Markets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit plan assets fair value	$ 2,821	$ 2,393