Fair Value Disclosures - Recurring Basis (Details) - USD ($) $ in Thousands	May 31, 2019	May 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate lock agreements	$ 36,400
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	96,645	$ 138,724
Total assets at fair value	96,645	138,724
Interest rate lock agreements	36,393
Total liabilities at fair value	36,393
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	96,645	138,724
Total assets at fair value	96,645	138,724
Interest rate lock agreements	0
Total liabilities at fair value	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Total assets at fair value	0	0
Interest rate lock agreements	36,393
Total liabilities at fair value	36,393
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Total assets at fair value	0	$ 0
Interest rate lock agreements	0
Total liabilities at fair value	$ 0