Fair value (Details 2) - USD ($)
$ in Thousands
Sep. 30, 2016
Dec. 31, 2015
Financial assets [Abstract]    
Investment securities available for sale $ 26,772 $ 37,919
Assets held for sale 841 12,631
Fair Value, Inputs, Level 1 [Member] | Reported Value Measurement [Member]    
Financial assets [Abstract]    
Cash 16,281 17,076
Investment securities available for sale 3,011 3,307
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]    
Financial assets [Abstract]    
Cash 16,281 17,076
Investment securities available for sale 3,011 3,307
Fair Value, Inputs, Level 2 [Member] | Reported Value Measurement [Member]    
Financial assets [Abstract]    
Cash equivalents 15,477 186
Investment securities available for sale 23,761 34,612
Federal Home Loan Bank stock 725 685
Loans held for sale 16,093 14,373
Loans 317,479 286,262
Impaired loans 15,198 18,862
Assets held for sale 841 12,631
Other real estate owned 3,621 6,190
Accrued interest receivable 2,354 2,060
Financial liabilities [Abstract]    
Deposits 379,220 364,848
FHLB borrowings 8,200 6,000
Trust preferred securities 8,764 8,764
Other borrowings 215 508
Accrued interest payable 64 1,346
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]    
Financial assets [Abstract]    
Cash equivalents 15,477 186
Investment securities available for sale 23,761 34,612
Federal Home Loan Bank stock 725 685
Loans held for sale 16,093 14,373
Loans 314,663 274,230
Impaired loans 15,198 18,862
Assets held for sale 841 12,631
Other real estate owned 3,621 6,190
Accrued interest receivable 2,354 2,060
Financial liabilities [Abstract]    
Deposits 379,661 365,294
FHLB borrowings 8,208 6,004
Trust preferred securities 9,162 8,984
Other borrowings 215 508
Accrued interest payable 64 1,346
Fair Value, Inputs, Level 3 [Member] | Reported Value Measurement [Member]    
Financial assets [Abstract]    
Impaired loans 859 1,647
Other real estate owned 0 59
Bank owned life insurance 7,269 7,130
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]    
Financial assets [Abstract]    
Impaired loans 859 1,647
Other real estate owned 0 59
Bank owned life insurance $ 7,269 $ 7,130