Net Loss (Gain) on Marketable Securities (Detail) - USD ($) $ in Thousands	3 Months Ended
Aug. 31, 2022	Aug. 31, 2021
Net Loss (Gain) on Marketable Securities
Unrealized losses (gains) on marketable equity securities	$ 6,513	$ (3,218)
Realized losses (gains) on marketable equity securities	129	(269)
Realized (gains) losses on available-for-sale debt securities	(36)	11
Net loss (gain) on marketable securities	$ 6,606	$ (3,476)

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 https://asc.fasb.org/extlink&oid=126953954&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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