Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	May 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	23.60%	29.40%
Federal statutory rate	35.00%	35.00%
Discrete tax benefit for excess tax benefits related to equity compensation	$ 10,400,000
Undistributed foreign earnings	377,000,000		$ 377,300,000
Deferred income tax liability	98,100,000		$ 98,500,000
Provision for deferred income taxes	$ 0