Summary of Accounts Receivable Net of Allowances and Net Contract Assets (Liabilities) (Detail) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2020	May 31, 2019
Disaggregation Of Revenue [Line Items]
Accounts receivable, less allowance	$ 1,137,957	$ 1,232,350
Contract assets	25,249	21,628
Contract liabilities - short-term	(25,288)	(25,896)
Net Contract Liabilities	(39)	$ (4,268)
Change in Contract with Customer, Asset and Liability [Abstract]
Change in accounts receivable, less allowance	(94,393)
Change in contract assets	3,621
Change in Net Contract Liabilities	$ 4,229
Percentage of change in accounts receivable, less allowance	(7.70%)
Percentage of change in contract assets	16.70%
Percentage of change in Net Contract Liabilities	(99.10%)
Short-term
Change in Contract with Customer, Asset and Liability [Abstract]
Change in contract liabilities	$ 608
Percentage of change in contract liabilities	(2.30%)