Revenue - Revenue related to performance obligations (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized	$ 169,948
Revenue, remaining performance obligation, expected timing of satisfaction, start date [Axis]: 2020-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized, period	9 months
Revenue expected to be recognized	$ 93,580
Revenue, remaining performance obligation, expected timing of satisfaction, start date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized, period	1 year
Revenue expected to be recognized	$ 48,682
Revenue, remaining performance obligation, expected timing of satisfaction, start date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized, period	1 year
Revenue expected to be recognized	$ 20,239
Revenue, remaining performance obligation, expected timing of satisfaction, start date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue expected to be recognized, period
Revenue expected to be recognized	$ 7,447