Goodwill, Service Contracts and Other Assets - Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2019	Aug. 31, 2018
Goodwill, Service Contracts and Other Assets [Abstract]
Amortization expense for service contracts and other assets	$ 34,600	$ 33,000
2020 (remaining nine months)	100,846
2021	120,954
2022	109,078
2023	90,379
2024	79,144
Thereafter	274,800
Total future amortization expense	$ 775,201