Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2017
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 33,510	$ 20,525	$ 19,103
Additions	10,761	13,358	6,446
Deductions	6,462	373	5,024
Balance at End of Year	37,809	33,510	20,525
Reserve for Obsolete Inventory
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	37,043	38,305	32,716
Additions	2,346	1,335	10,049
Deductions	6,711	2,597	4,460
Balance at End of Year	$ 32,678	$ 37,043	$ 38,305