Fair Value Measurement - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018	May 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets Measured On Nonrecurring Basis Change In Unrealized Gain Loss Recorded In Earnings	$ 0	$ 0	$ 0	$ 0
Impaired Financing Receivable, Recorded Investment	11,097,000		11,097,000		$ 11,853,000
Collateral Pledged
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 0		$ 0		$ 0