Derivative Instruments and Hedging Activities - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
Aug. 31, 2018	May 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Impact to fair value of derivative assets and liabilities as a result of recognition on a net basis	$ 1,392,000	$ 351,000
Losses in accumulated other comprehensive income expected to be reclassified into net earnings	3,847,000
Losses in accumulated other comprehensive income expected to be reclassified into net earnings, tax	$ 1,205,000

The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80845-113994

Name:	us-gaap_DerivativeInstrumentsGainLossReclassificationFromAccumulatedOCIToIncomeEstimatedNetAmountToBeTransferred
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration