Loans and Leases - Reserve for Loan and Lease Losses and Recorded Investment in Loans and Leases (Details 5) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	$ 690				$ 2,158
Ending balance: collectively evaluated for impairment	26,406				28,844
Total ending balance	27,096	30,502	29,870		31,002	32,601	30,898
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	40,754				41,262
Ending balance: collectively evaluated for impairment	1,428,757				1,405,011
Loans and Leases Held for Investment	1,469,511		1,446,406	[1]	1,446,273
Commercial, financial and agricultural [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	428				374
Ending balance: collectively evaluated for impairment	10,827				9,350
Total ending balance	11,255	12,021	11,262		9,724	10,877	9,630
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	4,232				5,861
Ending balance: collectively evaluated for impairment	471,893				461,389
Loans and Leases Held for Investment	476,125				467,250
Real Estate - Commercial and Construction [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	262				1,784
Ending balance: collectively evaluated for impairment	9,977				13,941
Total ending balance	10,239	12,316	13,317		15,725	16,092	15,288
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	35,976				34,886
Ending balance: collectively evaluated for impairment	575,012				567,209
Loans and Leases Held for Investment	610,988				602,095
Real Estate - Residential Secured for Business Purpose [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	684				856
Total ending balance	684	834	823		856	1,019	1,333
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	175				215
Ending balance: collectively evaluated for impairment	32,645				32,442
Loans and Leases Held for Investment	32,820				32,657
Real Estate - Residential and Home Equity Secured for Personal Purpose [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	946				696
Total ending balance	946	884	735		696	696	544
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	323				250
Ending balance: collectively evaluated for impairment	230,067				218,329
Loans and Leases Held for Investment	230,390				218,579
Loans to individuals [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	606				630
Total ending balance	606	719	730		630	695	734
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	48				50
Ending balance: collectively evaluated for impairment	42,578				42,240
Loans and Leases Held for Investment	42,626				42,290
Lease financings [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	1,184				1,612
Total ending balance	1,184	1,161	1,344		1,612	1,912	1,950
Loans and leases held for investment:
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	76,562				83,402
Loans and Leases Held for Investment	76,562				83,402
Unallocated [Member]
Reserve for loan and lease losses:
Ending balance: collectively evaluated for impairment	2,182				1,759
Total ending balance	$ 2,182	$ 2,567	$ 1,659		$ 1,759	$ 1,310	$ 1,419

[1] Note: The consolidated balance sheet at December 31, 2011 has been derived from the audited financial statements at that date but does not include all of the information and footnotes required by U. S. generally accepted accounting principles for complete financial statements. Certain amounts have been reclassified to conform to the current-year presentation. See accompanying notes to the unaudited consolidated financial statements.