Quarterly report pursuant to Section 13 or 15(d)

Allowance for Loan and Lease Losses - Summary of Investment in Loans Disaggregated Based on Method of Evaluating Impairment (Details)

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Allowance for Loan and Lease Losses - Summary of Investment in Loans Disaggregated Based on Method of Evaluating Impairment (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Financing Receivable Allowance For Credit Losses [Line Items]    
Loans - Recorded Investment, Individually Evaluated for Impairment $ 3,879 $ 3,986
Loans - Recorded Investment, Collectively Evaluated for Impairment 878,222 865,133
Allowance for Credit Loss, Individually Evaluated for Impairment 1,169 1,361
Allowance for Credit Loss, Collectively Evaluated for Impairment 4,558 4,291
Commercial and Industrial Loans    
Financing Receivable Allowance For Credit Losses [Line Items]    
Loans - Recorded Investment, Individually Evaluated for Impairment 1,882 2,194
Loans - Recorded Investment, Collectively Evaluated for Impairment 135,518 132,846
Allowance for Credit Loss, Individually Evaluated for Impairment 1,148 1,226
Allowance for Credit Loss, Collectively Evaluated for Impairment 1,758 1,820
Real Estate | 1-4 Single Family Residential Loans    
Financing Receivable Allowance For Credit Losses [Line Items]    
Loans - Recorded Investment, Individually Evaluated for Impairment 1,458 1,292
Loans - Recorded Investment, Collectively Evaluated for Impairment 236,924 231,218
Allowance for Credit Loss, Individually Evaluated for Impairment   119
Allowance for Credit Loss, Collectively Evaluated for Impairment 887 783
Real Estate | Construction, Land and Development    
Financing Receivable Allowance For Credit Losses [Line Items]    
Loans - Recorded Investment, Collectively Evaluated for Impairment 143,646 139,470
Allowance for Credit Loss, Collectively Evaluated for Impairment 540 441
Real Estate | Commercial Real Estate Loans (Including Multifamily)    
Financing Receivable Allowance For Credit Losses [Line Items]    
Loans - Recorded Investment, Individually Evaluated for Impairment 433 447
Loans - Recorded Investment, Collectively Evaluated for Impairment 289,138 285,284
Allowance for Credit Loss, Collectively Evaluated for Impairment 1,032 898
Consumer Loans and Leases    
Financing Receivable Allowance For Credit Losses [Line Items]    
Loans - Recorded Investment, Individually Evaluated for Impairment 106 53
Loans - Recorded Investment, Collectively Evaluated for Impairment 20,718 22,683
Allowance for Credit Loss, Individually Evaluated for Impairment 21 16
Allowance for Credit Loss, Collectively Evaluated for Impairment 154 182
Municipal and Other Loans    
Financing Receivable Allowance For Credit Losses [Line Items]    
Loans - Recorded Investment, Collectively Evaluated for Impairment 52,278 53,632
Allowance for Credit Loss, Collectively Evaluated for Impairment $ 187 $ 167