Quarterly report pursuant to Section 13 or 15(d)

Service Revenue (Summary of Changes in Deferred Revenue Related to Material Rights Performance Obligations) (Details)

v3.20.2
Service Revenue (Summary of Changes in Deferred Revenue Related to Material Rights Performance Obligations) (Details) - USD ($)
$ in Millions
3 Months Ended
Aug. 31, 2020
Aug. 31, 2019
Service Revenue [Abstract]    
Balance, beginning of period $ 42.6 $ 45.7
Deferral of revenue 4.0 5.5
Recognition of unearned revenue (6.4) (6.7)
Balance, end of period $ 40.2 $ 44.5