ALLOWANCE FOR LOAN LOSSES: ALLOWANCE FOR LOAN LOSSES: (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	$ 4,806	$ 7,034	$ 8,565
Added	570	1,279	613
Charged Off	(105)	(153)	(430)
Payments	(1,077)	(3,354)	(1,714)
December 31,	4,194	4,806	7,034
Commercial
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	145	2,709	3,386
Added	0	0	0
Charged Off	0	0	0
Payments	(134)	(2,564)	(677)
December 31,	11	145	2,709
Residential
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	4,043	3,611	4,447
Added	195	984	227
Charged Off	(24)	(16)	(289)
Payments	(729)	(536)	(774)
December 31,	3,485	4,043	3,611
Consumer
Financing Receivable, Impaired, Troubled Debt Restructuring [Roll Forward]
January 1,	618	714	732
Added	375	295	386
Charged Off	(81)	(137)	(141)
Payments	(214)	(254)	(263)
December 31,	$ 698	$ 618	$ 714