Summary of Accounts Receivable Net of Allowances and Net Contract Assets (Liabilities) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2018	May 31, 2018
Disaggregation Of Revenue [Line Items]
Accounts receivable, less allowance	$ 1,070,626	$ 1,113,818
Contract assets	23,580	18,212
Contract liabilities - short-term	(26,702)	(23,335)
Net Contract Liabilities	(3,122)	$ (5,123)
Change in Contract with Customer, Asset and Liability [Abstract]
Change in accounts receivable, less allowance	(43,192)
Change in contract assets	5,368
Change in Net Contract Liabilities	$ 2,001
Percentage of change in accounts receivable, less allowance	(3.90%)
Percentage of change in contract assets	29.50%
Percentage of change in Net Contract Liabilities	(39.10%)
Short-term
Change in Contract with Customer, Asset and Liability [Abstract]
Change in contract liabilities	$ (3,367)
Percentage of change in contract liabilities	14.40%