ALLOWANCE FOR LOAN LOSSES: ALLOWANCE FOR LOAN LOSSES: Loans Modified as Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	$ 4,206	$ 4,194	$ 4,806
Added	1,300	996	570
Charged Off	(111)	(164)	(105)
Payments	(596)	(820)	(1,077)
December 31,	4,799	4,206	4,194
Commercial
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	0	11	145
Added	407	0	0
Charged Off	0	0	0
Payments	0	(11)	(134)
December 31,	407	0	11
Residential
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	3,589	3,485	4,043
Added	491	692	195
Charged Off	(29)	(6)	(24)
Payments	(365)	(582)	(729)
December 31,	3,686	3,589	3,485
Consumer
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	617	698	618
Added	402	304	375
Charged Off	(82)	(158)	(81)
Payments	(231)	(227)	(214)
December 31,	$ 706	$ 617	$ 698