Loans and Leases - Summary of Major Loan and Lease Categories (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	$ 3,361,925	$ 3,081,287
Total Loans and Leases Held for Investment, Acquired	456,473	538,780
Total Loans and Leases Held for Investment	3,818,398	3,620,067	$ 3,510,170
Unearned Lease Income, Originated	(14,700)	(14,243)
Unearned Lease Income, Acquired	0	0
Unearned lease income, included in the above table	(14,700)	(14,243)
Net deferred costs, Originated	4,060	4,669
Net deferred costs, Acquired	0	0
Net deferred costs, included in the above table	4,060	4,669
Overdraft Deposits, Originated	98	222
Overdraft Deposits, Acquired	0	0
Overdraft deposits included in the above table	98	222
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	880,961	833,100
Total Loans and Leases Held for Investment, Acquired	45,199	63,111
Total Loans and Leases Held for Investment	926,160	896,211	905,167
Real Estate-Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	1,373,093	1,235,681
Total Loans and Leases Held for Investment, Acquired	270,551	306,460
Total Loans and Leases Held for Investment	1,643,644	1,542,141
Real Estate-Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	204,602	171,244
Total Loans and Leases Held for Investment, Acquired	4,284	4,592
Total Loans and Leases Held for Investment	208,886	175,836
Real Estate-Residential Secured for Business Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	267,014	250,800
Total Loans and Leases Held for Investment, Acquired	71,698	91,167
Total Loans and Leases Held for Investment	338,712	341,967	294,103
Real Estate Residential Secured For Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	296,734	260,654
Total Loans and Leases Held for Investment, Acquired	54,689	60,920
Total Loans and Leases Held for Investment	351,423	321,574
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	175,351	171,884
Total Loans and Leases Held for Investment, Acquired	9,909	12,386
Total Loans and Leases Held for Investment	185,260	184,270
Loans to Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	31,048	28,156
Total Loans and Leases Held for Investment, Acquired	143	144
Total Loans and Leases Held for Investment	31,191	28,300	27,588
Lease Financings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	133,122	129,768
Total Loans and Leases Held for Investment, Acquired	0	0
Total Loans and Leases Held for Investment	$ 133,122	$ 129,768	$ 130,154