Revenue Recognition (Performance Obligation) (Details) $ in Millions	Dec. 31, 2018 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 4.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Disaggregation of Revenue [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 0.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months