Basis of Presentation - Performance Obligation Expected Satisfaction (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Amount	$ 97,034
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Expected Timing	9 months
Amount	$ 22,582
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Expected Timing	1 year
Amount	$ 36,817
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Expected Timing	1 year
Amount	$ 37,635