Loans and Leases (Schedule of Modifications for Troubled Debt Restructurings) (Detail) (TDRs [Member], USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2014 Loans		Sep. 30, 2013 Loans		Sep. 30, 2014 Loans		Sep. 30, 2013 Loans
Financing Receivable Modifications [Line Items]
Number Of Loans	48		102		95		407
Pre-Modification Recorded Investment	$ 2,684,000		$ 13,336,000		$ 6,767,000		$ 38,405,000
Post-Modification Recorded Investment	2,684,000		13,336,000		6,767,000		38,405,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	5,000	[1]	0	[1]
Financial Effect Of Modification On Interest	3,000	[2]	45,000	[2]	(5,000)	[2]	(223,000)	[2]
Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	6		56		50		119
Recorded Investment Subsequently Defaulted	209,000		5,915,000		5,391,000		15,295,000
Originated Loans And Leases [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	47		99		90		386
Pre-Modification Recorded Investment	2,627,000		12,962,000		6,123,000		35,569,000
Post-Modification Recorded Investment	2,627,000		12,962,000		6,123,000		35,569,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	5,000	[1]	0	[1]
Financial Effect Of Modification On Interest	3,000	[2]	66,000	[2]	40,000	[2]	(159,000)	[2]
Originated Loans And Leases [Member] | Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	6		53		46		111
Recorded Investment Subsequently Defaulted	209,000		5,849,000		2,745,000		14,692,000
Purchased Loans And Leases [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	1		3		5		21
Pre-Modification Recorded Investment	57,000		374,000		644,000		2,836,000
Post-Modification Recorded Investment	57,000		374,000		644,000		2,836,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	(21,000)	[2]	(45,000)	[2]	(64,000)	[2]
Purchased Loans And Leases [Member] | Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	0		3		4		8
Recorded Investment Subsequently Defaulted	0		66,000		2,646,000		603,000
Commercial, Financial, And Agricultural [Member] | Combination Of Modification Types [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	0		1		0		2
Pre-Modification Recorded Investment	0		51,000		0		292,000
Post-Modification Recorded Investment	0		51,000		0		292,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	0	[2]	0	[2]	0	[2]
Commercial, Financial, And Agricultural [Member] | Bankruptcies And Maturity Date Extensions [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	3		6		9		29
Pre-Modification Recorded Investment	124,000		845,000		226,000		9,379,000
Post-Modification Recorded Investment	124,000		845,000		226,000		9,379,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	(6,000)	[2]	0	[2]	(6,000)	[2]
Commercial, Financial, And Agricultural [Member] | Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	0		3		11		15
Recorded Investment Subsequently Defaulted	0		33,000		2,027,000		7,334,000
Real Estate - Construction [Member] | Combination Of Modification Types [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	0		0		0		0
Pre-Modification Recorded Investment	0		0		0		0
Post-Modification Recorded Investment	0		0		0		0
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	0	[2]	0	[2]	0	[2]
Real Estate - Construction [Member] | Bankruptcies And Maturity Date Extensions [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	0		0		0		2
Pre-Modification Recorded Investment	0		0		0		137,000
Post-Modification Recorded Investment	0		0		0		137,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	0	[2]	0	[2]	0	[2]
Real Estate - Construction [Member] | Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	0		1		0		3
Recorded Investment Subsequently Defaulted	0		117,000		0		254,000
Real Estate Secured - Residential [Member] | Combination Of Modification Types [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	0		8		7		25
Pre-Modification Recorded Investment	0		1,313,000		1,100,000		3,815,000
Post-Modification Recorded Investment	0		1,313,000		1,100,000		3,815,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	51,000	[2]	(8,000)	[2]	(21,000)	[2]
Real Estate Secured - Residential [Member] | Bankruptcies And Maturity Date Extensions [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	25		37		41		136
Pre-Modification Recorded Investment	2,397,000		3,715,000		4,786,000		12,038,000
Post-Modification Recorded Investment	2,397,000		3,715,000		4,786,000		12,038,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	3,000	[2]	0	[2]	3,000	[2]	0	[2]
Real Estate Secured - Residential [Member] | Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	3		17		11		30
Recorded Investment Subsequently Defaulted	181,000		862,000		578,000		2,152,000
Real Estate Secured - Commercial [Member] | Combination Of Modification Types [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	0		0		1		1
Pre-Modification Recorded Investment	0		0		375,000		1,436,000
Post-Modification Recorded Investment	0		0		375,000		1,436,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	0	[2]	0	[2]	(196,000)	[2]
Real Estate Secured - Commercial [Member] | Bankruptcies And Maturity Date Extensions [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	0		7		0		19
Pre-Modification Recorded Investment	0		7,066,000		0		9,565,000
Post-Modification Recorded Investment	0		7,066,000		0		9,565,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	0	[2]	0	[2]	0	[2]
Real Estate Secured - Commercial [Member] | Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	0		4		4		7
Recorded Investment Subsequently Defaulted	0		4,640,000		2,599,000		5,087,000
Consumer [Member] | Combination Of Modification Types [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	0		1		0		1
Pre-Modification Recorded Investment	0		26,000		0		26,000
Post-Modification Recorded Investment	0		26,000		0		26,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	0	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	0	[2]	0	[2]	0	[2]
Consumer [Member] | Bankruptcies And Maturity Date Extensions [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans	20		42		37		192
Pre-Modification Recorded Investment	163,000		320,000		280,000		1,717,000
Post-Modification Recorded Investment	163,000		320,000		280,000		1,717,000
Financial Effect Of Modification On Recorded Investment	0	[1]	0	[1]	5,000	[1]	0	[1]
Financial Effect Of Modification On Interest	0	[2]	0	[2]	0	[2]	0	[2]
Consumer [Member] | Subsequently Defaulted [Member]
Financing Receivable Modifications [Line Items]
Number Of Loans Subsequently Defaulted	3		31		24		64
Recorded Investment Subsequently Defaulted	$ 28,000		$ 263,000		$ 187,000		$ 468,000

[1] Financial effects impacting the recorded investment include principal payments, advances, charge-offs, and capitalized past-due amounts.

[2] Represents the present value of interest rate concessions discounted at the effective rate of the original loan.