Fair Value: Fair Value, by Balance Sheet Grouping (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investments available-for-sale	$ 136,601,000	$ 142,170,000
FHLB stock	7,009,000	7,310,000
Derivative Asset, Fair Value, Gross Asset	426,000	1,662,000
Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash on hand and in banks	10,094,000	8,122,000
Interest-earning deposits	12,896,000	8,888,000
Investments available-for-sale	136,601,000	142,170,000
Loans receivable, net	1,096,499,000	1,012,114,000
FHLB stock	7,009,000	7,310,000
Accrued interest receivable	4,138,000	4,068,000
Derivative Asset, Fair Value, Gross Asset	426	1,662,000
Deposits	513,959,000	450,033,000
Certificates of deposit, retail	430,418,000	390,101,000
Certificates of deposit, brokered	94,556,000	97,466,000
Advances from the FHLB	137,706,000	146,357,000
Accrued interest payable	285,000	478,000
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash on hand and in banks	10,094,000	8,122,000
Interest-earning deposits	12,896,000	8,888,000
Investments available-for-sale	136,601,000	142,170,000
Loans receivable, net	1,108,462,000	1,022,904,000
FHLB stock	7,009,000	7,310,000
Accrued interest receivable	4,138,000	4,068,000
Derivative Asset, Fair Value, Gross Asset	426	1,662,000
Deposits	513,959,000	450,033,000
Certificates of deposit, retail	425,103,000	391,174,000
Certificates of deposit, brokered	94,472,000	97,825,000
Advances from the FHLB	137,700,000	146,500,000
Accrued interest payable	285,000	478,000
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash on hand and in banks	10,094,000	8,122,000
Interest-earning deposits	12,896,000	8,888,000
Investments available-for-sale	0	0
Loans receivable, net	0	0
FHLB stock	0	0
Accrued interest receivable	0	0
Derivative Asset, Fair Value, Gross Asset	0	0
Deposits	513,959,000	450,033,000
Certificates of deposit, retail	0	0
Certificates of deposit, brokered	0	0
Advances from the FHLB	0	0
Accrued interest payable	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash on hand and in banks	0	0
Interest-earning deposits	0	0
Investments available-for-sale	136,601,000	142,170,000
Loans receivable, net	0	0
FHLB stock	7,009,000	7,310,000
Accrued interest receivable	4,138,000	4,068,000
Derivative Asset, Fair Value, Gross Asset	426	1,662,000
Deposits	0	0
Certificates of deposit, retail	430,418,000	390,101,000
Certificates of deposit, brokered	94,556,000	97,466,000
Advances from the FHLB	137,706,000	146,357,000
Accrued interest payable	285,000	478,000
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash on hand and in banks	0	0
Interest-earning deposits	0	0
Investments available-for-sale	0	0
Loans receivable, net	1,096,499,000	1,012,114,000
FHLB stock	0	0
Accrued interest receivable	0	0
Derivative Asset, Fair Value, Gross Asset	0	0
Deposits	0	0
Certificates of deposit, retail	0	0
Certificates of deposit, brokered	0	0
Advances from the FHLB	0	0
Accrued interest payable	$ 0	$ 0