Loans (Narrative) (Details)
12 Months Ended
Dec. 31, 2015
USD ($)
loan
Dec. 31, 2014
USD ($)
property
loan
Dec. 31, 2013
USD ($)
Dec. 31, 2012
USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loans and leases receivable, allowance percentage 0.93% 0.97%    
Total number of loans | loan 38 31    
90 or greater days delinquent $ 10,740,000 $ 10,263,000    
Total non-accrual loans 11,433,000 10,263,000    
Loan portfolio 918,894,000 872,129,000 $ 808,240,000  
Allowance for loan loss $ 8,540,000 $ 8,481,000    
Loans added to troubled debt restructuring | loan 10 19    
Loans removed from troubled debt restructuring | loan 4 8    
Amount of loans added to troubled debt restructuring $ 3,200,000 $ 16,600,000    
Amount of loans removed from troubled debt restructuring 2,100,000 2,400,000    
Interest income recognized on outstanding TDR loans 508,000 563,000    
TDR loan principal curtailment 677,000 810,000    
Charge-offs 1,458,000 2,642,000 1,162,000  
Loans, carrying amount 909,200,000 862,409,000    
Non-accrual performing loans 693,000      
90 or greater days 10,740,000 10,263,000    
Loans receivable from related parties $ 28,105,000 $ 24,403,000 16,601,000 $ 6,987,000
Number of TDR loans | loan 30 24    
Number of accrual TDR loans | loan 23 19    
Financing receivable post modification recorded investment $ 18,568,000 $ 18,136,000    
Accrual TDR loans 13,133,000 13,249,000    
Financing Receivable Troubled Debt Restructuring [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Nonaccrual loans with deferred collection of principal and interest for one year $ 1,700,000 $ 1,000,000    
Number of accruing loans 90 days or greater past due | loan 3 1    
Nine Troubled Debt Restructuring Loans with Reserves [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Specific reserves for TDR loans $ 1,300,000      
Number of TDR loans | loan 9      
Financing receivable post modification recorded investment $ 3,600,000      
Five Troubled Debt Restructuring Loans with Reserves [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Specific reserves for TDR loans   $ 251,000    
Number of TDR loans | loan   5    
Financing receivable post modification recorded investment   $ 2,500,000    
Two Substandard Customer Loan Relationships [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Amount of loans added to troubled debt restructuring   10,100,000    
First Substandard Customer Loan Relationship [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Amount of loans added to troubled debt restructuring   8,600,000    
Charge-offs   500,000    
Loans, carrying amount 8,100,000 8,200,000    
Second Substandard Customer Loan Relationship [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Amount of loans added to troubled debt restructuring   3,800,000    
Charge-offs   $ 843,000    
Number of finished lots taken into OREO | property   11    
Loans, carrying amount 1,400,000 $ 1,900,000    
Other real estate, carrying amount $ 486,000 757,000    
Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loans and leases receivable, allowance percentage 80.00%      
Loan portfolio $ 613,479,000 $ 561,080,000 476,648,000  
Percentage status of loan in portfolio 5.30% 4.40%    
Amount of loans added to troubled debt restructuring $ 3,200,000      
Charge-offs 78,000 $ 350,000 140,000  
90 or greater days $ 3,480,000 $ 3,824,000    
Number of TDR loans | loan 13 9    
Financing receivable post modification recorded investment $ 11,897,000 $ 10,438,000    
Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 67,246,000 73,625,000 94,176,000  
Charge-offs 432,000 1,134,000 480,000  
90 or greater days $ 1,361,000 $ 1,587,000    
Number of TDR loans | loan 7 6    
Financing receivable post modification recorded investment $ 1,384,000 $ 2,262,000    
Commercial Equipment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 29,931,000 26,152,000 23,738,000  
Charge-offs 818,000 10,000 35,000  
90 or greater days $ 348,000 $ 286,000    
Number of TDR loans | loan 2 2    
Financing receivable post modification recorded investment $ 123,000 $ 154,000    
Residential First Mortgages [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 149,967,000 152,837,000 159,147,000  
Charge-offs 30,000 94,000 $ 348,000  
90 or greater days $ 1,948,000 $ 533,000    
Number of TDR loans | loan 3 3    
Financing receivable post modification recorded investment $ 881,000 $ 906,000    
Adjustable Rate Residential First Mortgage [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 33,600,000 $ 27,400,000    
Percentage status of loan in portfolio 3.70% 3.10%    
Nineteen Loans Representing Six Customer Relationships [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Nonaccrual loans with deferred collection of principal and interest for one year $ 3,800,000      
Sixteen Loans Representing Six Customer Relationships [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Nonaccrual loans with deferred collection of principal and interest for one year   $ 3,900,000    
Nonaccrual Loans With No Impairment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Total non-accrual loans 10,500,000 9,300,000    
Interest due to debt 953,000 781,000    
Nonaccrual Loans With Impairment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Total non-accrual loans 902,000 1,000,000    
Interest due to debt $ 34,000 64,000    
Minimum [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Debt maturity period 3 years      
Minimum [Member] | Residential First Mortgages [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Debt maturity period 10 years      
Maximum [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Debt maturity period 20 years      
Maximum [Member] | Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Debt maturity period 5 years      
Maximum [Member] | Residential First Mortgages [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Debt maturity period 30 years      
Unrated [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 70,661,000 74,955,000    
Unrated [Member] | Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 11,281,000 12,296,000    
Unrated [Member] | Commercial Equipment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 10,074,000 7,173,000    
Pass [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 519,330,000 451,256,000    
Pass [Member] | Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 51,569,000 53,844,000    
Pass [Member] | Commercial Equipment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 19,610,000 18,517,000    
Special Mention [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 1,095,000 4,383,000    
Special Mention [Member] | Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 49,000    
Special Mention [Member] | Commercial Equipment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio    
Substandard [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 22,393,000 $ 30,486,000    
Substandard [Member] | Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 4,110,000 7,436,000    
Substandard [Member] | Commercial Equipment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio 110,000 462,000    
Substandard [Member] | Nineteen Loans Representing Six Customer Relationships [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 8,100,000      
Percentage status of loan in portfolio 71.00%      
Substandard [Member] | Sixteen Loans Representing Six Customer Relationships [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio   $ 8,800,000    
Percentage status of loan in portfolio   86.00%    
Doubtful [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio    
Doubtful [Member] | Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 286,000    
Doubtful [Member] | Commercial Equipment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 137,000    
Loss [Member] | Commercial Real Estate [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio    
Loss [Member] | Commercial Loans [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio    
Loss [Member] | Commercial Equipment [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio    
Performing Financing Receivable [Member] | Residential First Mortgages [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 148,019,000 $ 152,304,000    
Nonperforming Financing Receivable [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
90 or greater days delinquent   $ 10,300,000    
Increase (decrease) in loans 1,100,000      
Loan portfolio $ 11,400,000      
Percentage status of loan in portfolio 1.24% 1.18%    
Nonperforming Financing Receivable [Member] | Residential First Mortgages [Member]        
Accounts, Notes, Loans and Financing Receivable [Line Items]        
Loan portfolio $ 1,948,000 $ 533,000