Discontinued Operations - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2019	May 31, 2018	May 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business	$ 3,200	$ 127,835	$ 28,276
Gain on sale of business	3,200	96,400	26,917
Discontinued Services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business		$ 127,800
Storage Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business			2,400
Shred-it Partnership
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business	$ 3,200		$ 25,500