Pension Plan Assets Categorized Using Fair Value Hierarchy (Detail) - Pension Benefits - USD ($) $ in Thousands	May 31, 2020	May 31, 2019	May 31, 2018
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	$ 516,550	$ 496,865	$ 487,233
U.S. Plans | U.S. Treasury and other government
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	12,973	13,854
U.S. Plans | State and Municipal Debt Obligations
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	508	386
U.S. Plans | Foreign Covered Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	715	1,031
U.S. Plans | Mortgage-backed securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	23,824	20,075
U.S. Plans | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	34,317	26,204
U.S. Plans | Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets		13,392
U.S. Plans | Large Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	19,589
U.S. Plans | Small Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets		15,720
U.S. Plans | Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	241,426	265,969
U.S. Plans | Mutal Funds - Multi-class
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	118,205	78,143
U.S. Plans | Debt Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	33,993	22,215
U.S. Plans | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	30,830	39,704
U.S. Plans | Limited Partner
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	170	172
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	194,874	187,112	188,960
Non-U.S. Plans | Foreign Covered Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	603	227
Non-U.S. Plans | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	67	123
Non-U.S. Plans | Pooled Equity Securities Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	78,472	78,733
Non-U.S. Plans | Pooled Funds Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	87,610	79,061
Non-U.S. Plans | Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	27,267	27,843
Non-U.S. Plans | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	855	1,125
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	50,419	68,816
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Plans | Mid Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets		13,392
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Plans | Large Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	19,589
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Plans | Small Cap Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets		15,720
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Plans | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	30,830	39,704
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	67	123
Quoted Prices in Active Markets for Identical Assets (Level 1) | Non-U.S. Plans | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	67	123
Significant Other Observable Inputs (Level 2) | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	465,961	427,877
Significant Other Observable Inputs (Level 2) | U.S. Plans | U.S. Treasury and other government
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	12,973	13,854
Significant Other Observable Inputs (Level 2) | U.S. Plans | State and Municipal Debt Obligations
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	508	386
Significant Other Observable Inputs (Level 2) | U.S. Plans | Foreign Covered Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	715	1,031
Significant Other Observable Inputs (Level 2) | U.S. Plans | Mortgage-backed securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	23,824	20,075
Significant Other Observable Inputs (Level 2) | U.S. Plans | Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	34,317	26,204
Significant Other Observable Inputs (Level 2) | U.S. Plans | Equity Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	241,426	265,969
Significant Other Observable Inputs (Level 2) | U.S. Plans | Mutal Funds - Multi-class
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	118,205	78,143
Significant Other Observable Inputs (Level 2) | U.S. Plans | Debt Mutual Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	33,993	22,215
Significant Other Observable Inputs (Level 2) | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	167,540	159,146
Significant Other Observable Inputs (Level 2) | Non-U.S. Plans | Foreign Covered Bonds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	603	227
Significant Other Observable Inputs (Level 2) | Non-U.S. Plans | Pooled Equity Securities Funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	78,472	78,733
Significant Other Observable Inputs (Level 2) | Non-U.S. Plans | Pooled Funds Fixed Income Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	87,610	79,061
Significant Other Observable Inputs (Level 2) | Non-U.S. Plans | Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	855	1,125
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	27,437	28,015	$ 28,448
Significant Unobservable Inputs (Level 3) | U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	170	172
Significant Unobservable Inputs (Level 3) | U.S. Plans | Limited Partner
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	170	172
Significant Unobservable Inputs (Level 3) | Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	27,267	27,843
Significant Unobservable Inputs (Level 3) | Non-U.S. Plans | Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension plans with Plan Assets	$ 27,267	$ 27,843