Fair Value Measurements - Schedule of Fair Value of Financial Instruments Measured on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Feb. 28, 2019	May 31, 2018
Fair value on a recurring basis
Cash and cash equivalents	$ 80,859	$ 138,724
Total assets at fair value	80,859	138,724
Accrued liabilities:
Total liabilities at fair value	8,460
Interest rate lock agreements
Accrued liabilities:
Interest rate lock agreements	8,460
Level 1
Fair value on a recurring basis
Cash and cash equivalents	80,859	138,724
Total assets at fair value	80,859	138,724
Accrued liabilities:
Total liabilities at fair value	0
Level 1 | Interest rate lock agreements
Accrued liabilities:
Interest rate lock agreements	0
Level 2
Fair value on a recurring basis
Cash and cash equivalents	0	0
Total assets at fair value	0	0
Accrued liabilities:
Total liabilities at fair value	8,460
Level 2 | Interest rate lock agreements
Accrued liabilities:
Interest rate lock agreements	8,460
Level 3
Fair value on a recurring basis
Cash and cash equivalents	0	0
Total assets at fair value	0	$ 0
Accrued liabilities:
Total liabilities at fair value	0
Level 3 | Interest rate lock agreements
Accrued liabilities:
Interest rate lock agreements	$ 0