Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	May 31, 2016	May 31, 2015	May 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 693,520	$ 430,618	$ 374,442
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(11,933)	(38,538)	(9,787)
Cumulative translation adjustment on Shred-it	6,472	0	0
Change in fair value of derivatives	(12,156)	37	(228)
Amortization of interest rate lock agreements	1,952	1,952	1,952
Other	(738)	(350)	(1,632)
Other comprehensive loss	(16,403)	(36,899)	(9,695)
Comprehensive income	$ 677,117	$ 393,719	$ 364,747