Discontinued Operations - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business	$ 0	$ 3,200	$ 127,835
Gain on sale of business	0	3,200	96,400
Discontinued Services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business			$ 127,800
Shred-it Partnership
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business	$ 200	$ 3,200