Accumulated Other Comprehensive Income (Loss) - Reclassifications Out of Accumulated Other Comprehensive Income (Loss) (Details) - Reclassification out of Accumulated Other Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	May 31, 2016	May 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of interest rate locks	$ (3,130)	$ (3,130)
Tax benefit	1,178	1,178
Amortization of interest rate locks, net of tax	(1,952)	(1,952)
Cumulative translation adjustment on Shred-it	(10,381)	0
Tax benefit	3,909	0
Cumulative translation adjustment on Shred-it	$ (6,472)	$ 0