Loans and Leases - Age Analysis of Past Due Loans and Leases (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	$ 4,896	$ 14,266
60-89 Days Past Due	2,205	1,024
90 Days or more Past Due	18,164	20,728
Total Past Due	25,265	36,018
Current	1,516,219	1,445,844
Ending balance	1,541,484	1,481,862
Recorded Investment 90 Days or more Past Due and Accruing Interest	413	441
Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	386	586
60-89 Days Past Due	922	313
90 Days or more Past Due	2,904	754
Total Past Due	4,212	1,653
Current	418,604	466,768
Ending balance	422,816	468,421
Recorded Investment 90 Days or more Past Due and Accruing Interest	12
Real Estate-Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	148	8,266
60-89 Days Past Due	262
90 Days or more Past Due	4,932	5,894
Total Past Due	5,342	14,160
Current	595,011	515,962
Ending balance	600,353	530,122
Recorded Investment 90 Days or more Past Due and Accruing Interest
Real Estate-Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due		306
60-89 Days Past Due
90 Days or more Past Due	8,742	13,150
Total Past Due	8,742	13,456
Current	81,751	77,794
Ending balance	90,493	91,250
Recorded Investment 90 Days or more Past Due and Accruing Interest
Real Estate-Residential Secured for Business Purpose [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	87	1,663
60-89 Days Past Due	276	69
90 Days or more Past Due	161	103
Total Past Due	524	1,835
Current	36,795	33,344
Ending balance	37,319	35,179
Recorded Investment 90 Days or more Past Due and Accruing Interest
Real Estate-Residential Secured for Personal Purpose [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	1,370	1,617
60-89 Days Past Due		152
90 Days or more Past Due	617
Total Past Due	1,987	1,769
Current	147,177	144,757
Ending balance	149,164	146,526
Recorded Investment 90 Days or more Past Due and Accruing Interest
Real Estate-Home Equity Secured for Personal Purpose [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	278	276
60-89 Days Past Due	97	64
90 Days or more Past Due	100	54
Total Past Due	475	394
Current	94,870	82,333
Ending balance	95,345	82,727
Recorded Investment 90 Days or more Past Due and Accruing Interest	23	54
Loans to Individuals [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	445	551
60-89 Days Past Due	193	153
90 Days or more Past Due	319	347
Total Past Due	957	1,051
Current	39,043	42,729
Ending balance	40,000	43,780
Recorded Investment 90 Days or more Past Due and Accruing Interest	319	347
Lease Financing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	2,182	1,001
60-89 Days Past Due	455	273
90 Days or more Past Due	389	426
Total Past Due	3,026	1,700
Current	102,968	82,157
Ending balance	105,994	83,857
Recorded Investment 90 Days or more Past Due and Accruing Interest	$ 59	$ 40