Changes Recognized in Other Comprehensive Income, Postretirement Benefits (Detail) - Postretirement Benefits - USD ($) $ in Thousands	12 Months Ended
	May 31, 2020	May 31, 2019
Domestic
Changes in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain) arising during the year	$ 702	$ (283)
Amounts recognized as a component of net periodic benefit cost:
Amortization or curtailment recognition of prior service credit	219	219
Amortization or settlement recognition of net gain (loss)	66	26
Total recognized in other comprehensive loss (income)	987	(38)
Non-U.S. Plans
Changes in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain) arising during the year	(683)	3,801
Effect of exchange rates on amounts included in AOCI	(266)	(419)
Amounts recognized as a component of net periodic benefit cost:
Amortization or settlement recognition of net gain (loss)	(611)	(442)
Total recognized in other comprehensive loss (income)	$ (1,560)	$ 2,940