Loans and Leases - Troubled Debt Restructured Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013 Loans	Sep. 30, 2012 Loans	Sep. 30, 2013 Loans	Sep. 30, 2012 Loans
Accruing Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	4	3	5	17
Pre-Restructuring Outstanding Recorded Investment	$ 2,028	$ 3,352	$ 3,028	$ 7,364
Post-Restructuring Outstanding Recorded Investment	2,028	3,352	3,028	7,364
Related Allowance
Nonaccrual Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans				3
Pre-Restructuring Outstanding Recorded Investment				572
Post-Restructuring Outstanding Recorded Investment				572
Related Allowance
Commercial, financial and agricultural [Member] | Accruing Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans		2	1	10
Pre-Restructuring Outstanding Recorded Investment		1,731	1,000	3,404
Post-Restructuring Outstanding Recorded Investment		1,731	1,000	3,404
Related Allowance
Commercial, financial and agricultural [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans				2
Pre-Restructuring Outstanding Recorded Investment				448
Post-Restructuring Outstanding Recorded Investment				448
Related Allowance
Real estate-commercial real estate [Member] | Accruing Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	3	1	3	5
Pre-Restructuring Outstanding Recorded Investment	1,569	1,621	1,569	2,630
Post-Restructuring Outstanding Recorded Investment	1,569	1,621	1,569	2,630
Related Allowance
Real estate-commercial real estate [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans				1
Pre-Restructuring Outstanding Recorded Investment				124
Post-Restructuring Outstanding Recorded Investment				124
Related Allowance
Real estate-construction [Member] | Accruing Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1		1	2
Pre-Restructuring Outstanding Recorded Investment	459		459	1,330
Post-Restructuring Outstanding Recorded Investment	459		459	1,330
Related Allowance