Fair Value: Fair Value, by Balance Sheet Grouping (Details) - USD ($)
Dec. 31, 2016
Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Investments available-for-sale $ 129,260,000 $ 129,565,000
FHLB stock 8,031,000 6,137,000
Derivative Asset, Fair Value, Gross Asset 1,333,000 0
Carrying Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash on hand and in banks 5,779,000 5,713,000
Interest-earning deposits 25,573,000 99,998,000
Investments available-for-sale 129,260,000 129,565,000
Loans receivable, net 815,043,000 685,072,000
FHLB stock 8,031,000 6,137,000
Accrued interest receivable 3,147,000 2,968,000
Derivative Asset, Fair Value, Gross Asset 1,333  
Deposits 285,335,000 285,416,000
Certificates of deposit, retail 356,653,000 323,840,000
Certificates of deposit, brokered 75,488,000 66,151,000
Advances from the FHLB 171,500,000 125,500,000
Accrued interest payable 231,000 135,000
Estimated Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash on hand and in banks 5,779,000 5,713,000
Interest-earning deposits 25,573,000 99,998,000
Investments available-for-sale 129,260,000 129,565,000
Loans receivable, net 818,054,000 693,480,000
FHLB stock 8,031,000 6,137,000
Accrued interest receivable 3,147,000 2,968,000
Derivative Asset, Fair Value, Gross Asset 1,333  
Deposits 285,335,000 285,416,000
Certificates of deposit, retail 356,723,000 324,135,000
Certificates of deposit, brokered 75,431,000 66,947,000
Advances from the FHLB 170,221,000 125,466,000
Accrued interest payable 231,000 135,000
Level 1    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash on hand and in banks 5,779,000 5,713,000
Interest-earning deposits 25,573,000 99,998,000
Investments available-for-sale 0 0
Loans receivable, net 0 0
FHLB stock 0 0
Accrued interest receivable 0 0
Deposits 285,335,000 285,416,000
Certificates of deposit, retail 0 0
Certificates of deposit, brokered   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 129,260,000 129,565,000
Loans receivable, net 0 0
FHLB stock 8,031,000 6,137,000
Accrued interest receivable 3,147,000 2,968,000
Derivative Asset, Fair Value, Gross Asset 1,333  
Deposits 0 0
Certificates of deposit, retail 356,723,000 324,135,000
Certificates of deposit, brokered 75,431,000 66,947,000
Advances from the FHLB 170,221,000 125,466,000
Accrued interest payable 231,000 135,000
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 818,054,000 693,480,000
FHLB stock 0 0
Accrued interest receivable 0 0
Deposits 0 0
Certificates of deposit, retail 0 0
Certificates of deposit, brokered   0
Advances from the FHLB 0 0
Accrued interest payable $ 0 $ 0