Loans and Allowance for Loan Losses - Narrative (Details)	3 Months Ended			9 Months Ended
	Sep. 30, 2018 USD ($) contract property method component	Jun. 30, 2018 borrower	Sep. 30, 2017 contract	Sep. 30, 2018 USD ($) contract relationship property category method component borrower loan	Sep. 30, 2017 contract	Dec. 31, 2017 USD ($)
Financing Receivable, Impaired [Line Items]
Deferred loan origination fees and costs, net	$ 335,000			$ 335,000		$ 635,000
Allowance for loan losses, number of evaluation components | component	2			2
Impaired loans collectively evaluated	$ 1,700,000			$ 1,700,000		1,300,000
Impaired loans, related reserves	168,000			168,000		169,000
Liability for unfunded commitments	$ 284,000			$ 284,000		284,000
Total valuation methods used on impaired loans | method	3			3
Impaired loans, identified during the period				$ 2,900,000
Impaired loans, principal curtailment				1,300,000
Impaired loans, partial charge-offs				362,000
Reclassification to other real estate owned				720,000
Classification to performing loans				424,000
Foreclosed properties held	$ 1,700,000			$ 1,700,000
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			$ 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
Specific reserve allocations for TDR's	484,000			$ 484,000		439,000
Loans identified as impaired, remaining loans	$ 6,400,000			$ 6,400,000		6,400,000
Number of contracts | contract	0		1	4	1
Acquisition & Development
Financing Receivable, Impaired [Line Items]
Loans defaulted under the restructured terms				$ 3,700,000
Number of borrower defaulted | borrower		1		2
Number of loans to defaulted borrowers | loan				3
Commercial
Financing Receivable, Impaired [Line Items]
Forclosure of unrelated borrower | property	3			3
Residential
Financing Receivable, Impaired [Line Items]
Increase (decrease) in impaired loans (as a percentage)				42.00%
Number foreclosed properties held | property	8			8
Foreclosed properties held	$ 732,000			$ 732,000
Foreclosure of loan relationship | relationship				2
Forclosure of unrelated borrower | property	2			2
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	$ 1,700,000			$ 1,700,000
Investment in loans in the process of foreclosure, related allowance	$ 88,000			88,000
Total Recorded Investment In Impaired Financing Receivables | Credit Concentration Risk
Financing Receivable, Impaired [Line Items]
Increase (decrease) in impaired loans				$ (120,000)
Increase (decrease) in impaired loans (as a percentage)				(0.77%)
Troubled Debt Restructured Loans
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0
Accruing
Financing Receivable, Impaired [Line Items]
Loans identified as impaired, remaining loans	$ 2,600,000			$ 2,600,000		$ 5,900,000
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Commercial
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0		1	2	1
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Commercial | Acquisition & Development
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0		0	0	0
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Commercial | Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0		0	0	0
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Residential
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0		0	0	0
Accruing | Troubled Debt Restructured Loans | Portfolio Risk | Consumer
Financing Receivable, Impaired [Line Items]
Number of contracts | contract	0		0	1	0
Commercial Loan Relationship One | Residential
Financing Receivable, Impaired [Line Items]
Number foreclosed properties held | property	3			3
Foreclosed properties held	$ 395,000			$ 395,000
Commercial Loan Relationship Two | Residential
Financing Receivable, Impaired [Line Items]
Number foreclosed properties held | property	3			3
Foreclosed properties held	$ 174,000			$ 174,000
Commercial Loan Relationship Three | Residential
Financing Receivable, Impaired [Line Items]
Number foreclosed properties held | property	2			2
Foreclosed properties held	$ 163,000			$ 163,000
Other Loan Relationships | Residential
Financing Receivable, Impaired [Line Items]
Increase (decrease) in impaired loans (as a percentage)				58.00%
Foreclosed properties held	$ 1,000,000			$ 1,000,000