Fair Value Measurements - Schedule of Instruments on a Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Aug. 31, 2019	May 31, 2019
Fair value on a recurring basis
Cash and cash equivalents	$ 102,131	$ 96,645
Total assets at fair value	102,131	96,645
Long-term accrued liabilities:
Total liabilities at fair value	76,141	36,393
Interest rate lock agreements
Long-term accrued liabilities:
Interest rate lock agreements	76,141	36,393
Level 1
Fair value on a recurring basis
Cash and cash equivalents	102,131	96,645
Total assets at fair value	102,131	96,645
Long-term accrued liabilities:
Total liabilities at fair value	0	0
Level 1 | Interest rate lock agreements
Long-term accrued liabilities:
Interest rate lock agreements	0	0
Level 2
Fair value on a recurring basis
Cash and cash equivalents	0	0
Total assets at fair value	0	0
Long-term accrued liabilities:
Total liabilities at fair value	76,141	36,393
Level 2 | Interest rate lock agreements
Long-term accrued liabilities:
Interest rate lock agreements	76,141	36,393
Level 3
Fair value on a recurring basis
Cash and cash equivalents	0	0
Total assets at fair value	0	0
Long-term accrued liabilities:
Total liabilities at fair value	0	0
Level 3 | Interest rate lock agreements
Long-term accrued liabilities:
Interest rate lock agreements	$ 0	$ 0