Loans, Allowance for Credit Losses and Impaired Loans - Impaired loans (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Impaired loans with specific reserves - Recorded Investment	$ 3,230	$ 7,267
Impaired loans with specific reserves - Unpaid Principal Balance	3,230	7,395
Impaired loans with specific reserves - Interest Income Recognized	199	422
Impaired loans with specific reserves - Specific Reserve	937	1,042
Impaired loans with specific reserves - Average Recorded Investment	5,249	8,701
Impaired loans with no specific reserves - Recorded Investment	18,925	20,415
Impaired loans with no specific reserves - Unpaid Principal Balance	20,181	22,721
Impaired loans with no specific reserves - Interest Income Recognized	1,036	1,384
Impaired loans with no specific reserves - Average Recorded Investment	19,670	15,672
Impaired loans specific reserves - Recorded Investment	22,155	27,682
Impaired loans specific reserves - Unpaid Principal Balance	23,411	30,116
Impaired loans specific reserves - Interest Income Recognized	1,235	1,806
Impaired loans specific reserves - Average Recorded Investment	24,919	24,374
Loans
Carrying amount	626,607	625,513
Unamortized discounts on acquired loans	668	1,327
PCI loans
Loans
Carrying amount	810	1,110
Unamortized discounts on acquired loans	257
Individual evaluation for impairment not required	1,900
Other real estate secured
Financing Receivable, Impaired [Line Items]
Impaired loans with specific reserves - Recorded Investment	2,278	3,276
Impaired loans with specific reserves - Unpaid Principal Balance	2,278	3,276
Impaired loans with specific reserves - Interest Income Recognized	188	246
Impaired loans with specific reserves - Specific Reserve	47	412
Impaired loans with specific reserves - Average Recorded Investment	2,777	3,690
Impaired loans with no specific reserves - Recorded Investment	12,339	12,849
Impaired loans with no specific reserves - Unpaid Principal Balance	12,815	13,905
Impaired loans with no specific reserves - Interest Income Recognized	768	1,016
Impaired loans with no specific reserves - Average Recorded Investment	12,594	10,691
1 - 4 Family residential secured
Financing Receivable, Impaired [Line Items]
Impaired loans with specific reserves - Recorded Investment	738	3,947
Impaired loans with specific reserves - Unpaid Principal Balance	738	4,075
Impaired loans with specific reserves - Interest Income Recognized		174
Impaired loans with specific reserves - Specific Reserve	251	586
Impaired loans with specific reserves - Average Recorded Investment	2,343	4,989
Impaired loans with no specific reserves - Recorded Investment	4,261	5,761
Impaired loans with no specific reserves - Unpaid Principal Balance	5,041	7,011
Impaired loans with no specific reserves - Interest Income Recognized	158	256
Impaired loans with no specific reserves - Average Recorded Investment	5,011	3,902
Other
Financing Receivable, Impaired [Line Items]
Impaired loans with specific reserves - Recorded Investment	214	44
Impaired loans with specific reserves - Unpaid Principal Balance	214	44
Impaired loans with specific reserves - Interest Income Recognized	11	2
Impaired loans with specific reserves - Specific Reserve	639	44
Impaired loans with specific reserves - Average Recorded Investment	129	22
Impaired loans with no specific reserves - Recorded Investment	2,325	1,805
Impaired loans with no specific reserves - Unpaid Principal Balance	2,325	1,805
Impaired loans with no specific reserves - Interest Income Recognized	110	112
Impaired loans with no specific reserves - Average Recorded Investment	$ 2,065	$ 1,080

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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Amount of allowance for credit losses related to recorded investment.

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

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Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

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Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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