Discontinued Operations - Schedule of Discontinued Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense	$ 1,460	$ 15,786	$ 38,573
Gain (loss) on Shred-it	25,457	354,071	(3,851)
Net income from discontinued operations	23,422	244,915	28,065
Discontinued Operations | Storage Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenue	105,559	109,686	138,584
Income before income taxes, excluding gains (losses) from sale transactions and investments	10,622	13,242	9,253
Income tax expense	2,400	15,786	38,573
Gain (loss) on Shred-it	25,457	354,071	(3,851)
Income tax expense	(15,057)	(138,184)	(15,910)
Net income from discontinued operations	$ 23,422	$ 244,915	$ 28,065