Consolidated Condensed Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Nov. 30, 2015	Aug. 31, 2015	Nov. 30, 2014	Aug. 31, 2014	Nov. 30, 2015	Nov. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 345,100		$ 120,412		$ 445,281	$ 230,520
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(4,626)		(9,778)		(16,639)	(11,893)
Cumulative translation adjustment on investment in Shred-it	6,472		0		6,472	0
Change in fair value of derivatives	0		(21)		0	(4)
Amortization of interest rate lock agreements	488		488		976	976
Change in fair value of available-for-sale securities	(10)		3		(18)	3
Other comprehensive income (loss)	2,324	$ (11,533)	(9,308)	$ (1,610)	(9,209)	(10,918)
Comprehensive income	$ 347,424		$ 111,104		$ 436,072	$ 219,602