Loans and Allowance for Loan Losses - Narrative (Details)	3 Months Ended
	Mar. 31, 2018 USD ($) contract relationship loan property category method component borrower quarter	Mar. 31, 2017 USD ($) contract	Dec. 31, 2017 USD ($)
Financing Receivable, Impaired [Line Items]
Deferred loan origination fees and costs, net	$ 600,000		$ 635,000
Allowance for loan losses, number of evaluation components | component	2
Impaired loans collectively evaluated	$ 1,400,000		1,300,000
Impaired loans, related reserves	$ 173,000		169,000
Number of rolling quarters utilized in charge-off factor calculation | quarter	12
Liability for unfunded commitments	$ 284,000	$ 284,000
Total valuation methods used on impaired loans | method	3
Impaired loans, identified during the period	$ 1,000,000
Impaired loans, principal curtailment	307,000
Impaired loans, partial charge-offs	335,000
Reclassification to other real estate owned	720,000
Classification to performing loans	292,000
Foreclosed properties held	$ 1,900,000
Number of points in internal risk rating system | category	9
Number of categories in internal risk rating system considered as not criticized | category	6
Commercial relationship credit review threshold amount	$ 1,000,000
Past due period before loans placed in non-accrual status	90 days
Recent loan payment history before removal from non-accrual status	6 months
Prepayment performance of commercial loan	$ 3,200,000
Specific reserve allocations for TDR's	443,000		439,000
Loans identified as impaired, remaining loans	$ 6,400,000		6,400,000
Number of loans to defaulted borrowers | loan	0
Number of contracts | contract	1	0
Acquisition & Development
Financing Receivable, Impaired [Line Items]
Number of borrower defaulted | borrower	1
Commercial
Financing Receivable, Impaired [Line Items]
Loans identified as impaired, remaining loans	$ 128,000
Residential
Financing Receivable, Impaired [Line Items]
Increase (decrease) in impaired loans (as a percentage)	47.00%
Number foreclosed properties held | property	9
Foreclosed properties held	$ 890,000
Foreclosure of loan relationship | relationship	2
Forclosure of unrelated borrower | property	3
Consumer
Financing Receivable, Impaired [Line Items]
Number of additional collateralized loans in the process of foreclosure | loan	2
Investment in loans in the process of foreclosure	$ 329,000
Investment in loans in the process of foreclosure, related allowance	0
Total Recorded Investment In Impaired Financing Receivables | Credit Concentration Risk
Financing Receivable, Impaired [Line Items]
Increase (decrease) in impaired loans	$ (805,000)
Increase (decrease) in impaired loans (as a percentage)	(5.20%)
Troubled Debt Restructured Loans
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0	0
Borrower One | Acquisition & Development
Financing Receivable, Impaired [Line Items]
Loans defaulted under the restructured terms	$ 432,000
Accruing
Financing Receivable, Impaired [Line Items]
Loans identified as impaired, remaining loans	$ 5,600,000		$ 5,900,000
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Commercial
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	1	0
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Commercial | Acquisition & Development
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0	0
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Commercial | Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0	0
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Residential
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0	0
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Consumer
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0	0
Commercial Loan Relationship One | Residential
Financing Receivable, Impaired [Line Items]
Number foreclosed properties held | property	3
Foreclosed properties held	$ 395,000
Commercial Loan Relationship Two | Residential
Financing Receivable, Impaired [Line Items]
Number foreclosed properties held | property	3
Foreclosed properties held	$ 178,000
Commercial Loan Relationship Three | Residential
Financing Receivable, Impaired [Line Items]
Number foreclosed properties held | property	3
Foreclosed properties held	$ 317,000
Other Loan Relationships | Residential
Financing Receivable, Impaired [Line Items]
Increase (decrease) in impaired loans (as a percentage)	53.00%
Foreclosed properties held	$ 1,000,000