Net (Gain) Loss on Marketable Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
May 31, 2021	May 31, 2020	May 31, 2019
Net Loss (Gain) on Marketable Securities
Unrealized (gains) losses on marketable equity securities	$ (16,133)	$ (1,457)	$ 5,827
Realized (gains) losses on marketable equity securities	(22,680)	(237)	2,322
Realized losses on available-for-sale debt securities	39	65	217
Net (gain) loss on marketable securities	$ (38,774)	$ (1,629)	$ 8,366

Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(7)(c))
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

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Amount of unrealized and realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI).

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Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI).

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Amount of unrealized gain (loss) on investment in marketable security.

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