Revenue Recognition, Contracts with Customers - Revenue Remaining Performance Obligations (Details) $ in Millions	Jun. 30, 2019 USD ($)
Revenue from Contract with Customer [Abstract]
Total revenue, expected to be recognized	$ 11.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue from Contract with Customer [Abstract]
Total revenue, expected to be recognized	$ 5.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Revenue from Contract with Customer [Abstract]
Total revenue, expected to be recognized	$ 6.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, period	1 year