Loans and Leases - Summary of Major Loan and Lease Categories (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	$ 1,586,994	$ 1,541,484	$ 1,499,993
Unearned lease income, included in the above table	(13,742)	(14,439)
Net deferred costs, included in the above table	2,832	2,744
Overdraft deposits, included in the above table	68	62
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	447,993	422,816
Real Estate-Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	626,060	600,353
Real Estate-Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	76,735	90,493
Real Estate-Residential Secured for Business Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	35,284	37,319	32,329
Real Estate-Residential Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	162,352	149,164
Real Estate-Home Equity Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	98,880	95,345
Loans to Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	31,564	40,000	43,598
Lease Financings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans and leases held for investment, net of deferred income	$ 108,126	$ 105,994	$ 91,621