Pretax Net Actuarial (Loss), Prior Service (Cost) and Transition Assets/(Obligation) Recognized in Accumulated Other Comprehensive Income (Loss) not Affecting Retained Earnings, Postretirement (Detail) - Postretirement Benefits - USD ($) $ in Thousands	May 31, 2021	May 31, 2020
Domestic
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net actuarial (loss)	$ (497)	$ (386)
Prior service credits	281	448
Total recognized in accumulated other comprehensive income not affecting retained earnings	(216)	62
Non-U.S. Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net actuarial (loss)	(5,901)	(11,331)
Total recognized in accumulated other comprehensive income not affecting retained earnings	$ (5,901)	$ (11,331)