REVENUES: Receivables and Allowance for Uncollectible Accounts (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 4,869	$ 5,034
Additions to the allowance	1,744	2,040
Write-offs, net of recoveries	(3,317)	(2,939)
Balance at end of period	$ 3,296	$ 4,135
Allowance for uncollectible accounts as a percentage of customer receivables	2.20%	3.00%