Loans and Leases - Concessions Granted on Accruing and Nonaccrual Loans Restructured (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]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	4	3	5	17
Amount	$ 2,028	$ 3,352	$ 3,028	$ 7,364
Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				3
Amount				572
Real estate-commercial real estate [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	3	1	3	5
Amount	1,569	1,621	1,569	2,630
Real estate-commercial real estate [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				1
Amount				124
Real estate-construction [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	1		1	2
Amount	459		459	1,330
Commercial, financial and agricultural [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans		2	1	10
Amount		1,731	1,000	3,404
Commercial, financial and agricultural [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				2
Amount				448
Interest Only Term Extension [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans		1	1	9
Amount		1,621	1,000	4,913
Interest Only Term Extension [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Interest Only Term Extension [Member] | Real estate-commercial real estate [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans		1		3
Amount		1,621		2,267
Interest Only Term Extension [Member] | Real estate-commercial real estate [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Interest Only Term Extension [Member] | Real estate-construction [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				2
Amount				1,330
Interest Only Term Extension [Member] | Commercial, financial and agricultural [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans			1	4
Amount			1,000	1,316
Interest Only Term Extension [Member] | Commercial, financial and agricultural [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Reduction [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	1		1	4
Amount	756		756	409
Temporary Payment Reduction [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Reduction [Member] | Real estate-commercial real estate [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	1		1	1
Amount	756		756	188
Temporary Payment Reduction [Member] | Real estate-commercial real estate [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Reduction [Member] | Real estate-construction [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Reduction [Member] | Commercial, financial and agricultural [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				3
Amount				221
Temporary Payment Reduction [Member] | Commercial, financial and agricultural [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Suspension [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Suspension [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				3
Amount				572
Temporary Payment Suspension [Member] | Real estate-commercial real estate [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Suspension [Member] | Real estate-commercial real estate [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				1
Amount				124
Temporary Payment Suspension [Member] | Real estate-construction [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Suspension [Member] | Commercial, financial and agricultural [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Temporary Payment Suspension [Member] | Commercial, financial and agricultural [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans				2
Amount				448
Maturity Date Extension [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	3	2	3	4
Amount	1,272	1,731	1,272	2,042
Maturity Date Extension [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Maturity Date Extension [Member] | Real estate-commercial real estate [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	2		2	1
Amount	813		813	175
Maturity Date Extension [Member] | Real estate-commercial real estate [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount
Maturity Date Extension [Member] | Real estate-construction [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans	1		1
Amount	459		459
Maturity Date Extension [Member] | Commercial, financial and agricultural [Member] | Accruing Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans		2		3
Amount		1,731		1,867
Maturity Date Extension [Member] | Commercial, financial and agricultural [Member] | Nonaccrual Troubled Debt Restructured Loans [Member]
Concessions granted on accruing and non-accrual loans restructured
No. of Loans
Amount