Income (loss) before Income Taxes (Detail) - USD ($) $ in Thousands		12 Months Ended
		May 31, 2017	May 31, 2016	May 31, 2015
Income Tax Disclosure [Abstract]
Income Before Income Taxes, United States		$ 133,356	$ 310,695	$ 273,278
Income Before Income Taxes, Foreign		110,977	172,771	179,975
Income Before Income Taxes	[1]	$ 244,333	$ 483,466	$ 453,253

[1] The presentation includes a reconciliation of Income (Loss) Before Income Taxes, a measure defined by Generally Accepted Accounting Principles (GAAP) in the United States, to EBIT.