Summary of Significant Accounting Principles - Remaining Performance Obligation (Details) $ in Millions	Sep. 30, 2019 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligations expected to be satisfied	$ 630.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-09-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligations expected to be satisfied	$ 532.4
Performance obligations expected to be satisfied, percentage	84.00%
Performance obligations expected to be satisfied, expected timing	12 months