Loans and Leases (Troubled Debt Restructurings By Class Segment) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended				12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013		Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable Modifications [Line Items]
Total performing TDRs	$ 42,418				$ 42,418				$ 72,133
TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	42,418		69,975		42,418		69,975		72,133		40,938	63,822	67,775
Non-performing TDRs	19,522	[1],[2]	22,166	[1]	19,522	[1],[2]	22,166	[1]	22,676	[2]
Total TDRs	61,940				61,940				94,809
Performing TDRs	68.00%		76.00%		68.00%		76.00%		76.00%
Non-performing TDRs	32.00%		24.00%		32.00%		24.00%		24.00%
Commercial, Financial, And Agricultural [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	4,044				4,044				6,885
Real Estate - Construction [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	319				319				615
Real Estate Secured - Residential [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	20,231				20,231				31,623
Real Estate Secured - Commercial [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	16,780				16,780				31,295
Consumer [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	$ 1,044				$ 1,044				$ 1,715

[1] Included in Age Analysis of Past Due Financing Receivables.

[2] These loans are included in the 90 day past due and nonaccrual categories.