Loans and Allowance for Loan Losses - Age Analysis of Past Due Loans (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	$ 6,709	$ 5,376
60-89 Days Past Due	2,069	2,859
Greater than 90 Days	14,197	17,303
Total Past Due	22,975	25,538
Current	866,956	857,010
Total ending loans balance	889,931	882,548	862,220
Recorded Investment greater than 90 Days and Accruing	0	184
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	2,869	3,681
60-89 Days Past Due	1,901	1,004
Greater than 90 Days	10,215	12,398
Total Past Due	14,985	17,083
Current	400,768	396,922
Total ending loans balance	415,753	414,005	410,781
Recorded Investment greater than 90 Days and Accruing	0	0
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	1,308	0
60-89 Days Past Due	5	0
Greater than 90 Days	462	376
Total Past Due	1,775	376
Current	74,134	68,329
Total ending loans balance	75,909	68,705	73,457
Recorded Investment greater than 90 Days and Accruing	0	0
Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	1,094	394
60-89 Days Past Due	0	1,094
Greater than 90 Days	2,267	2,827
Total Past Due	3,361	4,315
Current	61,125	60,668
Total ending loans balance	64,486	64,983	61,012
Recorded Investment greater than 90 Days and Accruing	0	184
Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	730	630
60-89 Days Past Due	57	494
Greater than 90 Days	1,009	1,510
Total Past Due	1,796	2,634
Current	119,968	120,196
Total ending loans balance	121,764	122,830	125,298
Recorded Investment greater than 90 Days and Accruing	0	0
Indirect
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	299	645
60-89 Days Past Due	104	227
Greater than 90 Days	56	69
Total Past Due	459	941
Current	199,505	198,983
Total ending loans balance	199,964	199,924	178,433
Recorded Investment greater than 90 Days and Accruing
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
30-59 Days Past Due	409	26
60-89 Days Past Due	2	40
Greater than 90 Days	188	123
Total Past Due	599	189
Current	11,456	11,912
Total ending loans balance	12,055	12,101	13,239
Recorded Investment greater than 90 Days and Accruing	$ 0	$ 0