Goodwill, Service Contracts and Other Assets - Estimated Future Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Goodwill, Service Contracts and Other Assets [Abstract]
Amortization expense for service contracts and other assets	$ 35,300	$ 33,300	$ 69,900	$ 66,200
2020 (remaining six months)	68,366		68,366
2021	125,140		125,140
2022	113,263		113,263
2023	94,309		94,309
2024	82,990		82,990
Thereafter	284,200		284,200
Total future amortization expense	$ 768,268		$ 768,268