Annual report pursuant to Section 13 and 15(d)

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

v3.20.2
Service Revenue (Summary of Changes in Deferred Revenue Related to Material Right Performance Obligations) (Details) - USD ($)
$ in Millions
12 Months Ended
May 31, 2020
May 31, 2019
Service Revenue [Abstract]    
Balance, beginning of period $ 45.7 $ 46.4
Deferral of revenue 24.7 27.6
Recognition of unearned revenue (27.8) (28.3)
Balance, end of period $ 42.6 $ 45.7