Revenue Recognition - Remaining Performance Obligation (Details) $ in Millions	Jul. 31, 2019 USD ($)
Disaggregation of Revenue [Line Items]
Remaining performance obligation	$ 457.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-08-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation percentage	62.00%
Revenue remaining performance obligation, expected timing of satisfaction period	12 months
Billed consideration
Disaggregation of Revenue [Line Items]
Remaining performance obligation	$ 181.4
Unbilled consideration
Disaggregation of Revenue [Line Items]
Remaining performance obligation	$ 276.2