Unearned Revenue - Narratives (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 129,400
Customer arrangements with termination rights	$ 16,130	$ 19,367
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Percentage of remaining performance obligation expected to be recognized in period	72.00%
Period of remaining performance obligation expected to be recognized	12 months