Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Feb. 28, 2017	Feb. 29, 2016	Feb. 28, 2017	Feb. 29, 2016	May 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	25.40%	11.90%	4.80%	28.30%
Federal statutory rate	35.00%	35.00%	35.00%	35.00%
Discrete tax benefits for excess tax benefits related to equity compensation	$ 200,000		$ 11,500,000
Discrete tax benefits primarily related to reversal of tax contingency reserves and benefits related to the distribution of foreign earnings		$ 3,900,000
Undistributed foreign earnings	372,600,000		372,600,000		$ 377,300,000
Deferred income tax liability	96,300,000		96,300,000		$ 98,500,000
Provision for deferred income taxes	$ 0		$ 0