Service Revenue (Summary of Deferred Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction) (Details) $ in Millions	Feb. 28, 2021 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-06-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue, timing of satisfaction	3 months
Deferred revenue related to material rights	$ 6.1
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-06-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue, timing of satisfaction	1 year 3 months
Deferred revenue related to material rights	$ 18.2
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-06-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred revenue, timing of satisfaction	2 years 3 months
Deferred revenue related to material rights	$ 15.5