Loans and Leases - Accruing and Nonaccrual Troubled Debt Restructured Loans with Payment Defaults (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]
Accruing and nonaccrual troubled debt restructured loans with payment default
Number of Loans	0	1	0	4
Recorded Investment	$ 0	$ 1,000	$ 0	$ 1,230
Accrual Troubled Debt Restructuring Loans [Member] | Commercial, Financial and Agricultural [Member]
Accruing and nonaccrual troubled debt restructured loans with payment default
Number of Loans	0	1	0	4
Recorded Investment	0	1,000	0	1,230
Nonaccrual Troubled Debt Restructured Loans [Member]
Accruing and nonaccrual troubled debt restructured loans with payment default
Number of Loans	0	0	0	0
Recorded Investment	$ 0	$ 0	$ 0	$ 0