Goodwill, Service Contracts and Other Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	May 31, 2020	May 31, 2019	May 31, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 140.8	$ 134.0	$ 61.2
Capitalized contract costs
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	7 years
Noncompete and consulting agreements
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	5 years
Other
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	3 years
Service contracts
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period	14 years