Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	May 31, 2018	May 31, 2017	May 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 842,586	$ 480,708	$ 693,520
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	19,276	(10,252)	(11,933)
Cumulative translation adjustment on Shred-it	0	0	6,472
Change in fair value of cash flow hedges	0	31,136	(12,156)
Amortization of interest rate lock agreements	(933)	1,076	1,952
Other	1,029	(115)	(738)
Other comprehensive income (loss), net of tax expense (benefit) of $690, $19,118 and ($9,813), respectively	19,372	21,845	(16,403)
Comprehensive income (loss)	$ 861,958	$ 502,553	$ 677,117