Loans and Leases - Summary of Major Loan and Lease Categories (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	$ 3,715,327	$ 3,629,198
Total Loans and Leases Held for Investment, Acquired	352,552	377,376
Total Loans and Leases Held for Investment	4,067,879	4,006,574	$ 3,689,888
Imputed interest on lease financings, originated	(15,082)	(15,118)
Imputed interest of lease financings, acquired	0	0
Imputed interest on lease financings, included in the above table	(15,082)	(15,118)
Net deferred costs, Originated	4,426	3,930
Net deferred costs, Acquired	0	0
Net deferred costs, included in the above table	4,426	3,930
Overdraft Deposits, Originated	208	139
Overdraft Deposits, Acquired	0	0
Overdraft deposits included in the above table	208	139
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	910,493	913,166
Total Loans and Leases Held for Investment, Acquired	17,145	24,519
Total Loans and Leases Held for Investment	927,638	937,685	907,938
Real Estate-Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	1,576,250	1,507,579
Total Loans and Leases Held for Investment, Acquired	222,955	233,625
Total Loans and Leases Held for Investment	1,799,205	1,741,204
Real Estate-Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	216,964	215,513
Total Loans and Leases Held for Investment, Acquired	0	0
Total Loans and Leases Held for Investment	216,964	215,513
Real Estate-Residential Secured for Business Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	304,574	302,393
Total Loans and Leases Held for Investment, Acquired	56,348	60,403
Total Loans and Leases Held for Investment	360,922	362,796	333,361
Real Estate Residential Secured For Personal Purpose [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	361,488	338,451
Total Loans and Leases Held for Investment, Acquired	47,652	49,959
Total Loans and Leases Held for Investment	409,140	388,410
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	172,587	177,523
Total Loans and Leases Held for Investment, Acquired	8,311	8,728
Total Loans and Leases Held for Investment	180,898	186,251
Loans to Individuals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	32,462	32,617
Total Loans and Leases Held for Investment, Acquired	141	142
Total Loans and Leases Held for Investment	32,603	32,759	28,255
Lease Financings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans and Leases Held for Investment, Originated	140,509	141,956
Total Loans and Leases Held for Investment, Acquired	0	0
Total Loans and Leases Held for Investment	$ 140,509	$ 141,956	$ 129,740