Unearned Revenue - Narratives (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 126,000
Customer arrangements with termination rights	$ 12,057	$ 16,130
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percentage of remaining performance obligation expected to be recognized in period	74.00%
Period of remaining performance obligation expected to be recognized	12 months