Revenue Recognition - Disaggregated Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 7,085,120	$ 6,892,303	$ 6,476,632
Product concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	100.00%	100.00%	100.00%
Uniform Rental and Facility Services
Disaggregation of Revenue [Line Items]
Revenue	$ 5,643,494	$ 5,552,430	$ 5,247,124
Uniform Rental and Facility Services | Product concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	79.60%	80.60%	81.00%
First Aid and Safety Services
Disaggregation of Revenue [Line Items]
Revenue	$ 708,569	$ 619,470	$ 564,706
First Aid and Safety Services | Product concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	10.00%	9.00%	8.70%
Fire Protection Services
Disaggregation of Revenue [Line Items]
Revenue	$ 422,688	$ 405,467	$ 349,968
Fire Protection Services | Product concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	6.00%	5.90%	5.40%
Uniform Direct Sales
Disaggregation of Revenue [Line Items]
Revenue	$ 310,369	$ 314,936	$ 314,834
Uniform Direct Sales | Product concentration risk | Revenue
Disaggregation of Revenue [Line Items]
Concentration risk (as a percent)	4.40%	4.50%	4.90%