Accounts Receivable - Allowance (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 493	$ 647	$ 506	$ 353
Provisions (recoveries) for expected credit losses, net of adjustments	25	(218)	12	76
Balance, end of period	$ 518	$ 429	$ 518	$ 429