Summary of Significant Accounting Policies Allowance for credit losses (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($)
Unbilled Revenue
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 397
Provision for credit loss expense	244
Write-offs	(277)
Recoveries	38
Total ending allowance balance	402
Customer Receivables
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	374
Provision for credit loss expense	263
Write-offs	(242)
Recoveries	41
Total ending allowance balance	$ 436