Net (Gain) Loss on Marketable Securities (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Feb. 28, 2021	Feb. 29, 2020	Feb. 28, 2021	Feb. 29, 2020
Net (Gain) Loss on Marketable Securities
Unrealized (gains) losses on marketable equity securities	$ (6,650)	$ 8,079	$ (28,469)	$ (2,459)
Realized (gains) on marketable equity securities	(2,834)	(1,153)	(1,210)	(1,107)
Realized (gains) losses on available-for-sale debt securities	4	(8)	27	4
Net (gain) loss on marketable securities	$ (9,480)	$ 6,918	$ (29,652)	$ (3,562)

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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