Quarterly report [Sections 13 or 15(d)]

Segment Reporting - Schedule of Total Revenue, Net Income and Significant Expenses Used by the Chief Operating Decision Maker (Details)

v3.26.3
Segment Reporting - Schedule of Total Revenue, Net Income and Significant Expenses Used by the Chief Operating Decision Maker (Details) - USD ($)
$ in Millions
 3 Months Ended
Aug. 31, 2026
Aug. 31, 2025
Segment Reporting [Line Items]    
Total revenue $ 1,630.5 $ 1,540.0
Core business operations:    
Depreciation and amortization 109.8 109.3
Non-core business operations:    
Total expenses 1,011.3 998.1
Other income, net 10.9 23.8
Income before income taxes 565.0 497.5
Income tax expense 135.3 113.7
Net income 429.7 383.8
Single Reportable Segment [Member]    
Segment Reporting [Line Items]    
Total revenue 1,630.5 1,540.0
Non-core business operations:    
Total expenses 1,011.3 998.1
Interest expense, excluding Paycor acquisition-related costs (65.1) (68.2)
Other income, net 10.9 23.8
Income before income taxes 565.0 497.5
Income tax expense 135.3 113.7
Net income 429.7 383.8
Single Reportable Segment [Member] | Core [Member]    
Core business operations:    
Compensation-related expenses 526.8 530.0
PEO direct insurance costs 152.9 138.6
Depreciation and amortization 52.9 48.2
Other segment items [1] 213.2 196.5
Single Reportable Segment [Member] | Noncore [Member]    
Non-core business operations:    
Acquisition-related costs [2] $ 65.5 $ 84.8
[1] Other segment items include expenses related to professional services, marketing and advertising, technology and general overhead.
[2] Acquisition-related costs included in total expenses include the amortization of intangibles acquired in the acquisition of Paycor HCM, Inc. ("Paycor"), compensation costs related to the acquisition and integration of Paycor, including replacement awards, severance, and retention bonuses, and other acquisition-related costs.