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Revenue from Contracts with Customers - Narrative (Details)
3 Months Ended
Mar. 31, 2020
Disaggregation of Revenue [Line Items]  
Contract terms Generally, contracts are billed in arrears on a quarterly basis and have a three year duration, after which the customer can terminate the agreement with notice, generally from three to twelve months.
Minimum  
Disaggregation of Revenue [Line Items]  
Termination period 3 months
Maximum  
Disaggregation of Revenue [Line Items]  
Termination period 12 months