Allowance for Loan Losses, Loans by Class Modified as Troubled Debt Restructured Loans (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Financing Receivable, Modifications [Line Items]
Specific reserves	$ 401,000	$ 759,000
Troubled debt restructured loans	2,600,000	4,900,000
Commitments to lend additional amounts to customers with outstanding loans that are classified as troubled debt restructurings	0	0	0
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	18	19
Pre-Modification Outstanding Recorded Investment	2,033,000	4,846,000
Post-Modification Recorded Outstanding Investment	1,969,000	4,772,000
Increase in allowance for loan losses due to TDR	53,000	78,000
TDR's charge-offs	64,000	74,000
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		1
Recorded Investment		12,000
Period after which loan is considered to be in payment default	90 days
Charge offs on troubled debt restructurings that subsequently defaulted	0	12,000
Minimum [Member]
Financing Receivable, Modifications [Line Items]
Period of modifications involving a reduction of stated interest rate of the loan	2 years
Period of modifications involving extension of maturity date	6 years
Maximum [Member]
Financing Receivable, Modifications [Line Items]
Period of modifications involving a reduction of stated interest rate of the loan	5 years
Period of modifications involving extension of maturity date	10 years
Performing [Member]
Financing Receivable, Modifications [Line Items]
Troubled debt restructured loans, performing	2,300,000	4,700,000
Commercial Real Estate [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	1	3
Pre-Modification Outstanding Recorded Investment	116,000	3,224,000
Post-Modification Recorded Outstanding Investment	116,000	3,224,000
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		0
Recorded Investment		0
Agricultural Real Estate [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	0	0
Pre-Modification Outstanding Recorded Investment	0	0
Post-Modification Recorded Outstanding Investment	0	0
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		0
Recorded Investment		0
Real Estate Construction [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	0	0
Pre-Modification Outstanding Recorded Investment	0	0
Post-Modification Recorded Outstanding Investment	0	0
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		0
Recorded Investment		0
Residential 1st Mortgages [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	2	5
Pre-Modification Outstanding Recorded Investment	216,000	995,000
Post-Modification Recorded Outstanding Investment	201,000	940,000
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		0
Recorded Investment		0
Home Equity Lines and Loans [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	7	7
Pre-Modification Outstanding Recorded Investment	529,000	381,000
Post-Modification Recorded Outstanding Investment	480,000	362,000
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		1
Recorded Investment		12,000
Agricultural [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	4	1
Pre-Modification Outstanding Recorded Investment	858,000	140,000
Post-Modification Recorded Outstanding Investment	858,000	140,000
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		0
Recorded Investment		0
Commercial [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	3	2
Pre-Modification Outstanding Recorded Investment	273,000	82,000
Post-Modification Recorded Outstanding Investment	273,000	82,000
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		0
Recorded Investment		0
Consumer & Other [Member]
Loans by class modified as troubled debt restructured loans [Abstract]
Number of Loans	1	1
Pre-Modification Outstanding Recorded Investment	41,000	24,000
Post-Modification Recorded Outstanding Investment	41,000	24,000
Troubled debt restructurings that subsequently default [Abstract]
Number of Loans		0
Recorded Investment		$ 0