Loans and Leases - Credit Quality Indicators (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012		Mar. 31, 2012
Credit quality indicators
Loans and leases held for investment	$ 1,487,375	$ 1,481,862	[1]	$ 1,459,830
Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	468,437	468,421
Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment	551,761	530,122
Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment	79,285	91,250
Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment	31,755	35,179
Real estate-residential secured for personal purpose [Member]
Credit quality indicators
Loans and leases held for investment	143,487	146,526
Real estate-home equity secured for personal purpose [Member]
Credit quality indicators
Loans and leases held for investment	83,399	82,727
Loans to individuals [Member]
Credit quality indicators
Loans and leases held for investment	41,781	43,780
Lease financings [Member]
Credit quality indicators
Loans and leases held for investment	87,470	83,857
Grade:1. Cash Secured / 2. Fully Secured [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	2,525	2,263
Grade:1. Cash Secured / 2. Fully Secured [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment
Grade:1. Cash Secured / 2. Fully Secured [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment
Grade:1. Cash Secured / 2. Fully Secured [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment
Grade:3. Strong [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	7,209	5,227
Grade:3. Strong [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment	9,480	9,591
Grade:3. Strong [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment	6,285	3,907
Grade:3. Strong [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment
Grade:4. Satisfactory [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	35,666	40,747
Grade:4. Satisfactory [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment	23,842	25,837
Grade:4. Satisfactory [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment	1,801	1,783
Grade:4. Satisfactory [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment	119	335
Grade:5. Acceptable [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	265,423	260,042
Grade:5. Acceptable [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment	303,329	321,194
Grade:5. Acceptable [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment	21,400	26,331
Grade:5. Acceptable [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment	21,447	22,764
Grade:6. Pre-watch [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	104,615	106,436
Grade:6. Pre-watch [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment	154,423	110,476
Grade:6. Pre-watch [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment	33,017	42,190
Grade:6. Pre-watch [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment	6,486	8,458
Grade:7. Special Mention [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	33,447	31,825
Grade:7. Special Mention [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment	17,993	16,187
Grade:7. Special Mention [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment	805	548
Grade:7. Special Mention [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment	1,084	288
Grade:8. Substandard [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment	19,552	21,881
Grade:8. Substandard [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment	42,694	45,844
Grade:8. Substandard [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment	15,977	16,491
Grade:8. Substandard [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment	2,619	3,334
Grade:9. Doubtful [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment
Grade:9. Doubtful [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment		993
Grade:9. Doubtful [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment
Grade:9. Doubtful [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment
Grade:10. Loss [Member] | Commercial, financial and agricultural [Member]
Credit quality indicators
Loans and leases held for investment
Grade:10. Loss [Member] | Real estate-commercial [Member]
Credit quality indicators
Loans and leases held for investment
Grade:10. Loss [Member] | Real estate-construction [Member]
Credit quality indicators
Loans and leases held for investment
Grade:10. Loss [Member] | Real estate-residential secured for business purpose [Member]
Credit quality indicators
Loans and leases held for investment
Performing Financing Receivable [Member] | Real estate-residential secured for personal purpose [Member]
Credit quality indicators
Loans and leases held for investment	142,683	145,722
Performing Financing Receivable [Member] | Real estate-home equity secured for personal purpose [Member]
Credit quality indicators
Loans and leases held for investment	83,376	82,673
Performing Financing Receivable [Member] | Loans to individuals [Member]
Credit quality indicators
Loans and leases held for investment	41,517	43,395
Performing Financing Receivable [Member] | Lease financings [Member]
Credit quality indicators
Loans and leases held for investment	86,997	83,412
Nonperforming Financing Receivable [Member] | Real estate-residential secured for personal purpose [Member]
Credit quality indicators
Loans and leases held for investment	804	804
Nonperforming Financing Receivable [Member] | Real estate-home equity secured for personal purpose [Member]
Credit quality indicators
Loans and leases held for investment	23	54
Nonperforming Financing Receivable [Member] | Loans to individuals [Member]
Credit quality indicators
Loans and leases held for investment	264	385
Nonperforming Financing Receivable [Member] | Lease financings [Member]
Credit quality indicators
Loans and leases held for investment	$ 473	$ 445

[1] Note: The consolidated balance sheet at December 31, 2012 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. See accompanying notes to the unaudited consolidated financial statements.