Loans and Leases - Troubled Debt Restructured Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014 Loans	Sep. 30, 2013 Loans	Sep. 30, 2014 Loans	Sep. 30, 2013 Loans
Accrual Troubled Debt Restructuring Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	4	4	4	5
Pre- Restructuring Outstanding Recorded Investment	$ 2,424	$ 2,028	$ 2,424	$ 3,028
Post- Restructuring Outstanding Recorded Investment	2,424	2,028	2,424	3,028
Related Allowance	132	0	132	0
Accrual Troubled Debt Restructuring Loans [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	3	0	3	1
Pre- Restructuring Outstanding Recorded Investment	1,424	0	1,424	1,000
Post- Restructuring Outstanding Recorded Investment	1,424	0	1,424	1,000
Related Allowance	132	0	132	0
Accrual Troubled Debt Restructuring Loans [Member] | Real Estate-Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	3	1	3
Pre- Restructuring Outstanding Recorded Investment	1,000	1,569	1,000	1,569
Post- Restructuring Outstanding Recorded Investment	1,000	1,569	1,000	1,569
Related Allowance	0	0	0	0
Accrual Troubled Debt Restructuring Loans [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	1	0	1
Pre- Restructuring Outstanding Recorded Investment	0	459	0	459
Post- Restructuring Outstanding Recorded Investment	0	459	0	459
Related Allowance	0	0	0	0
Nonaccrual Troubled Debt Restructured Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	0	3	0
Pre- Restructuring Outstanding Recorded Investment	0	0	738	0
Post- Restructuring Outstanding Recorded Investment	0	0	738	0
Related Allowance	0	0	0	0
Nonaccrual Troubled Debt Restructured Loans [Member] | Real Estate-Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1	0
Pre- Restructuring Outstanding Recorded Investment			50	0
Post- Restructuring Outstanding Recorded Investment			50	0
Related Allowance			0	0
Nonaccrual Troubled Debt Restructured Loans [Member] | Real Estate-Residential Secured for Business Purpose [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			2	0
Pre- Restructuring Outstanding Recorded Investment			688	0
Post- Restructuring Outstanding Recorded Investment			688	0
Related Allowance			$ 0	$ 0