Investment Expense (Income), Net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Aug. 31, 2019	Aug. 31, 2018
Investments Debt And Equity Securities [Abstract]
Unrealized gains on trading securities	$ 0.6
Unrealized gains on marketable equity securities	$ 2.9
Gross gains realized on sales of marketable securities		$ 0.6
Gross losses realized on sales of marketable securities		0.1
Other than temporary impairment marketable securities		$ 0.1

Gross realized gains on sales of marketable securities.

No definition available.

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- Definition

Gross realized losses on sales of marketable securities.

+ References

No definition available.

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563

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- Definition

Amount of unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=116654751&loc=SL75117546-209714

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- Definition

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 8A
-URI http://asc.fasb.org/extlink&oid=118954083&loc=SL6284422-111562

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- References

No definition available.

+ Details

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