Description of the business and recent developments: Allowance for credit losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Description of the business and recent developments:
Balance	$ 1,976	$ 1,771
Current-period Provision for Expected Credit Losses	1,432	2,768
Write offs Charged Against Allowance (Write-offs)	(1,293)	(2,424)
Balance	2,115	2,115
Bad debt recoveries	$ 200	$ 400