Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	May 31, 2021	May 31, 2020
Deferred tax assets
Accounts receivable	$ 1,244	$ 1,246
Inventories	4,946	5,554
Accrued expenses	24,714	21,214
Net operating loss carry forwards	9,907	11,732
Stock-based compensation	6,076	6,931
Derivative contracts		1,920
Operating lease - ROU liability	7,642	7,294
Other	2,309	3,549
Total deferred tax assets	56,838	59,440
Valuation allowance for deferred tax assets	(9,124)	(11,178)
Net deferred tax assets	47,714	48,262
Deferred tax liabilities
Property, plant and equipment	(111,789)	(95,553)
Investment in affiliated companies, principally due to undistributed earnings	(24,034)	(15,884)
Operating lease - ROU asset	(7,102)	(6,241)
Derivative contracts	(15,343)
Other	(3,197)	(2,526)
Total deferred tax liability	(161,465)	(120,204)
Net deferred tax liability	$ (113,751)	$ (71,942)