v3.8.0.1
Allowance for Loan Losses - Bank's Allowance for Loan Losses (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Financing Receivable Allowance For Credit Losses [Line Items]                              
Beginning Balance       $ 15,400       $ 10,600       $ 10,150 $ 15,400 $ 10,600 $ 10,150
Provision for loan losses $ 900 $ 701 $ 1,092 69 $ 1,800 $ 1,231 $ 1,250 400 $ 1,200 $ 570 $ 753 150 2,762 4,681 2,673
Charge-offs                           (50) (2,223)
Recoveries                         238 169  
Ending Balance 18,400       15,400       10,600       18,400 15,400 10,600
Residential Properties                              
Financing Receivable Allowance For Credit Losses [Line Items]                              
Beginning Balance       6,669       6,799       6,546 6,669 6,799 6,546
Provision for loan losses                         3,046 (130) 253
Ending Balance 9,715       6,669       6,799       9,715 6,669 6,799
Commercial Real Estate                              
Financing Receivable Allowance For Credit Losses [Line Items]                              
Beginning Balance       2,983       1,813       1,499 2,983 1,813 1,499
Provision for loan losses                         1,416 1,051 624
Charge-offs                           (50) (310)
Recoveries                           169  
Ending Balance 4,399       2,983       1,813       4,399 2,983 1,813
Land and Construction                              
Financing Receivable Allowance For Credit Losses [Line Items]                              
Beginning Balance       233       103       67 233 103 67
Provision for loan losses                         162 130 36
Ending Balance 395       233       103       395 233 103
Commercial and Industrial Loans                              
Financing Receivable Allowance For Credit Losses [Line Items]                              
Beginning Balance       5,227       1,649       1,897 5,227 1,649 1,897
Provision for loan losses                         (1,841) 3,578 1,665
Charge-offs                             (1,913)
Recoveries                         238    
Ending Balance 3,624       5,227       1,649       3,624 5,227 1,649
Consumer Loans                              
Financing Receivable Allowance For Credit Losses [Line Items]                              
Beginning Balance       $ 288       $ 236       $ 141 288 236 141
Provision for loan losses                         (21) 52 95
Ending Balance $ 267       $ 288       $ 236       $ 267 $ 288 $ 236