Acquisitions - Narrative (Details)	12 Months Ended
	May 31, 2019 business	May 31, 2018 business
Uniform rental and facility services
Business Acquisition [Line Items]
Number of businesses acquired	5	5
First Aid and Safety Services
Business Acquisition [Line Items]
Number of businesses acquired	1	3
All Other
Business Acquisition [Line Items]
Number of businesses acquired	7	6
Income approach | Discount rate
Business Acquisition [Line Items]
Intangible asset measurement input	0.095