Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands	May 31, 2020	May 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt at carrying amount including current maturities	$ 703,060
Long-term Debt
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt at fair value including current maturities	740,678	$ 767,075
Long-term debt at carrying amount including current maturities	$ 699,665	$ 749,299