Loans and Leases (Troubled Debt Restructurings By Class Segment) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				12 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013		Dec. 31, 2012
Financing Receivable Modifications [Line Items]
Total performing TDRs	$ 39,555				$ 72,133
TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	39,555		65,773		72,133		67,775
Non-performing TDRs	20,884	[1],[2]	25,808	[1]	22,676	[2]
Total TDRs	60,439				94,809
Performing TDRs	65.00%		72.00%		76.00%
Non-performing TDRs	35.00%		28.00%		24.00%
Commercial, Financial, And Agricultural [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	5,264				6,885
Real Estate - Construction [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	325				615
Real Estate Secured - Residential [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	16,168				31,623
Real Estate Secured - Commercial [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	16,681				31,295
Consumer [Member] | TDRs [Member]
Financing Receivable Modifications [Line Items]
Total performing TDRs	$ 1,117				$ 1,715

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

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