Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended			6 Months Ended
	Nov. 30, 2016	Aug. 31, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015	May 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax expense (benefit) rate	(34.30%)		30.00%	(3.70%)	29.70%
Federal statutory rate	35.00%		35.00%	35.00%	35.00%
Discrete tax benefit for excess tax benefits related to equity compensation	$ 900,000	$ 10,400,000
Undistributed foreign earnings	368,800,000			$ 368,800,000		$ 377,300,000
Deferred income tax liability	95,300,000			95,300,000		$ 98,500,000
Provision for deferred income taxes	$ 0			$ 0