Consolidated Condensed Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Nov. 30, 2016	Aug. 31, 2016	Nov. 30, 2015	Aug. 31, 2015	Nov. 30, 2016	Nov. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 140,377		$ 345,100		$ 278,468	$ 445,281
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(7,650)		(4,626)		(7,535)	(16,639)
Cumulative translation adjustment on investment in Shred-it	0		6,472		0	6,472
Change in fair value of derivatives	26,390		0		14,353	0
Amortization of interest rate lock agreements	385		488		770	976
Change in fair value of available-for-sale securities	1		(10)		0	(18)
Other comprehensive income (loss)	19,126	$ (11,538)	2,324	$ (11,533)	7,588	(9,209)
Comprehensive income	$ 159,503		$ 347,424		$ 286,056	$ 436,072