Loans and Leases - Reserve for Loan and Lease Losses Roll Forward (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				$ 24,746				$ 29,870	$ 24,746	$ 29,870	$ 30,898
Charge-offs									(13,619)	(16,735)	(19,703)
Recoveries									2,139	1,576	1,196
Provision (recovery of provision)	1,614	4,094	3,446	2,074	2,382	2,210	1,343	4,100	11,228	10,035	17,479
Balance at end of year	24,494				24,746				24,494	24,746	29,870
Commercial, Financial and Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				11,594				11,262	11,594	11,262
Charge-offs									(3,213)	(9,974)
Recoveries									320	484
Provision (recovery of provision)									1,088	9,822
Balance at end of year	9,789				11,594				9,789	11,594
Real Estate-Commercial and Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				7,507				13,317	7,507	13,317
Charge-offs									(8,667)	(4,803)
Recoveries									1,104	334
Provision (recovery of provision)									8,836	(1,341)
Balance at end of year	8,780				7,507				8,780	7,507
Real Estate-Residential Secured for Business Purpose [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				639				823	639	823
Charge-offs									(112)
Recoveries									13	60
Provision (recovery of provision)									522	(244)
Balance at end of year	1,062				639				1,062	639
Real Estate-Residential and Home Equity Secured for Personal Purpose [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				980				735	980	735
Charge-offs									(195)	(156)
Recoveries									13	7
Provision (recovery of provision)									486	394
Balance at end of year	1,284				980				1,284	980
Loans to Individuals [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				679				730	679	730
Charge-offs									(641)	(578)
Recoveries									174	130
Provision (recovery of provision)									482	397
Balance at end of year	694				679				694	679
Lease Financing [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				1,326				1,344	1,326	1,344
Charge-offs									(791)	(1,224)
Recoveries									515	561
Provision (recovery of provision)									235	645
Balance at end of year	1,285				1,326				1,285	1,326
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning balance				2,021				1,659	2,021	1,659
Charge-offs
Recoveries
Provision (recovery of provision)									(421)	362
Balance at end of year	$ 1,600				$ 2,021				$ 1,600	$ 2,021