Loans and Leases - Summary of Major Loan and Lease Categories (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	$ 1,883,563	$ 1,626,625
Total Loans and Leases Held for Investment, Acquired	295,450
Total Loans and Leases Held for Investment	2,179,013	1,626,625
Unearned Lease Income, Originated	(13,829)	(14,131)
Unearned Lease Income, Acquired	0
Unearned lease income, included in the above table	(13,829)
Net deferred costs, Originated	4,244	3,218
Net deferred costs, Acquired	0
Net deferred costs, included in the above table	4,244
Overdraft Deposits, Originated	35	50
Overdraft Deposits, Acquired	0
Overdraft Deposits	35
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	479,980	457,827
Total Loans and Leases Held for Investment, Acquired	24,535
Total Loans and Leases Held for Investment	504,515	457,827
Real Estate-Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	759,342	628,478
Total Loans and Leases Held for Investment, Acquired	126,550
Total Loans and Leases Held for Investment	885,892	628,478
Real Estate-Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	91,904	79,887
Total Loans and Leases Held for Investment, Acquired	4,637
Total Loans and Leases Held for Investment	96,541	79,887
Real Estate-Residential Secured for Business Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	94,280	36,932
Total Loans and Leases Held for Investment, Acquired	124,503
Total Loans and Leases Held for Investment	218,783	36,932
Real Estate-Residential Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	177,850	166,850
Total Loans and Leases Held for Investment, Acquired	3,305
Total Loans and Leases Held for Investment	181,155	166,850
Real Estate-Home Equity Secured for Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	125,361	108,250
Total Loans and Leases Held for Investment, Acquired	11,594
Total Loans and Leases Held for Investment	136,955	108,250
Loans to Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	29,406	29,941
Total Loans and Leases Held for Investment, Acquired	326
Total Loans and Leases Held for Investment	29,732	29,941
Lease Financings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	125,440	118,460
Total Loans and Leases Held for Investment, Acquired	0
Total Loans and Leases Held for Investment	$ 125,440	$ 118,460