Fair Value: Balance Sheet Grouping (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments available-for-sale	$ 141,581,000	$ 142,170,000
FHLB stock	5,701,000	7,310,000
Derivative fair value asset	450,000	1,662,000
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash on hand and in banks	8,119,000	8,122,000
Interest-earning deposits with banks	22,579,000	8,888,000
Investments available-for-sale	0	0
Loans receivable, net	0	0
FHLB stock	0	0
Accrued interest receivable	0	0
Derivative fair value asset	0	0
Deposits	432,813,000	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, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash on hand and in banks	0	0
Interest-earning deposits with banks	0	0
Investments available-for-sale	141,581,000	142,170,000
Loans receivable, net	0	0
FHLB stock	5,701,000	7,310,000
Accrued interest receivable	4,650,000	4,068,000
Derivative fair value asset	450,000	1,662,000
Deposits	0	0
Certificates of deposit, retail	416,959,000	390,101,000
Certificates of deposit, brokered	181,127,000	97,466,000
Advances from the FHLB	105,555,000	146,357,000
Accrued interest payable	461,000	478,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash on hand and in banks	0	0
Interest-earning deposits with banks	0	0
Investments available-for-sale	0	0
Loans receivable, net	1,044,364,000	1,012,114,000
FHLB stock	0	0
Accrued interest receivable	0	0
Derivative fair value 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
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash on hand and in banks	8,119,000	8,122,000
Interest-earning deposits with banks	22,579,000	8,888,000
Investments available-for-sale	141,581,000	142,170,000
Loans receivable, net	1,052,676,000	1,022,904,000
FHLB stock	5,701,000	7,310,000
Accrued interest receivable	4,650,000	4,068,000
Derivative fair value asset	450,000	1,662,000
Deposits	432,813,000	450,033,000
Certificates of deposit, retail	412,134,000	391,174,000
Certificates of deposit, brokered	180,763,000	97,825,000
Advances from the FHLB	105,000,000	146,500,000
Accrued interest payable	461,000	478,000
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash on hand and in banks	8,119,000	8,122,000
Interest-earning deposits with banks	22,579,000	8,888,000
Investments available-for-sale	141,581,000	142,170,000
Loans receivable, net	1,044,364,000	1,012,114,000
FHLB stock	5,701,000	7,310,000
Accrued interest receivable	4,650,000	4,068,000
Derivative fair value asset	450,000	1,662,000
Deposits	432,813,000	450,033,000
Certificates of deposit, retail	416,959,000	390,101,000
Certificates of deposit, brokered	181,127,000	97,466,000
Advances from the FHLB	105,555,000	146,357,000
Accrued interest payable	$ 461,000	$ 478,000