Loans (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Ending allowance balance attributable to loans:
Allowance for loan losses, Individually evaluated for impairment	$ 795		$ 1,265
Allowance for loan losses, Collectively evaluated for impairment	11,583		11,122
Allowance for loan losses, Modified in a troubled debt restructuring	1,271		228
Total ending allowance balance	13,649	13,690	12,615	12,252	11,715	10,820
Loans:
Loans individually evaluated for impairment	15,249		14,696
Loans collectively evaluated for impairment	887,982		830,385
Loans modified in a troubled debt restructuring	10,383		7,688
Total ending loans balance	913,614		852,769
Commercial, Industrial, and Agricultural [Member]
Ending allowance balance attributable to loans:
Allowance for loan losses, Individually evaluated for impairment	498		329
Allowance for loan losses, Collectively evaluated for impairment	3,975		4,182
Allowance for loan losses, Modified in a troubled debt restructuring	0		0
Total ending allowance balance	4,473	5,115	4,511	3,722	3,770	3,517
Loans:
Loans individually evaluated for impairment	6,927		6,115
Loans collectively evaluated for impairment	252,694		247,209
Loans modified in a troubled debt restructuring	285		0
Total ending loans balance	259,906		253,324
Commercial Mortgages [Member]
Ending allowance balance attributable to loans:
Allowance for loan losses, Individually evaluated for impairment	229		917
Allowance for loan losses, Collectively evaluated for impairment	3,392		3,325
Allowance for loan losses, Modified in a troubled debt restructuring	1,271		228
Total ending allowance balance	4,892	4,553	4,470	4,854	4,399	3,511
Loans:
Loans individually evaluated for impairment	7,698		8,457
Loans collectively evaluated for impairment	239,235		226,366
Loans modified in a troubled debt restructuring	10,098		7,688
Total ending loans balance	257,031		242,511
Residential Real Estate [Member]
Ending allowance balance attributable to loans:
Allowance for loan losses, Individually evaluated for impairment	68		19
Allowance for loan losses, Collectively evaluated for impairment	2,264		1,972
Allowance for loan losses, Modified in a troubled debt restructuring	0		0
Total ending allowance balance	2,332	2,225	1,991	2,011	1,900	1,916
Loans:
Loans individually evaluated for impairment	624		124
Loans collectively evaluated for impairment	335,172		298,504
Loans modified in a troubled debt restructuring	0		0
Total ending loans balance	335,796		298,628
Consumer [Member]
Ending allowance balance attributable to loans:
Allowance for loan losses, Individually evaluated for impairment	0		0
Allowance for loan losses, Collectively evaluated for impairment	1,706		1,404
Allowance for loan losses, Modified in a troubled debt restructuring	0		0
Total ending allowance balance	1,706	1,568	1,404	1,412	1,400	1,561
Loans:
Loans individually evaluated for impairment	0		0
Loans collectively evaluated for impairment	55,979		53,471
Loans modified in a troubled debt restructuring	0		0
Total ending loans balance	55,979		53,471
Credit Cards [Member]
Ending allowance balance attributable to loans:
Allowance for loan losses, Individually evaluated for impairment	0		0
Allowance for loan losses, Collectively evaluated for impairment	79		71
Allowance for loan losses, Modified in a troubled debt restructuring	0		0
Total ending allowance balance	79	81	71	97	104	96
Loans:
Loans individually evaluated for impairment	0		0
Loans collectively evaluated for impairment	4,572		4,412
Loans modified in a troubled debt restructuring	0		0
Total ending loans balance	4,572		4,412
Overdrafts [Member]
Ending allowance balance attributable to loans:
Allowance for loan losses, Individually evaluated for impairment	0		0
Allowance for loan losses, Collectively evaluated for impairment	167		168
Allowance for loan losses, Modified in a troubled debt restructuring	0		0
Total ending allowance balance	167	148	168	156	142	219
Loans:
Loans individually evaluated for impairment	0		0
Loans collectively evaluated for impairment	330		423
Loans modified in a troubled debt restructuring	0		0
Total ending loans balance	$ 330		$ 423