Loans and Asset Quality Information (Summary of Major Categories of Total Loans Outstanding) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 4,394,984	$ 4,247,765	$ 4,190,139
Unamortized net deferred loan costs	1,560	1,299	489
Total loans	$ 4,396,544	$ 4,249,064	4,190,628
Percentage	100.00%	100.00%
SBA Loans
Loans and Leases Receivable Disclosure [Line Items]
Total loans	$ 160,256	$ 150,777
SBA Loans, Guaranteed Portion
Loans and Leases Receivable Disclosure [Line Items]
Total loans	47,280	53,205
SBA Loans, Unguaranteed Portion
Loans and Leases Receivable Disclosure [Line Items]
Total loans	112,976	97,572
SBA Loans, Sold Portion
Loans and Leases Receivable Disclosure [Line Items]
Total loans	308,842	230,424
Commercial, financial, and agricultural
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 486,768	$ 457,037	435,730
Percentage	11.00%	11.00%
Real estate, commercial \| Real estate – construction, land development & other land loans
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 471,326	$ 518,976	559,450
Percentage	11.00%	12.00%
Real estate, commercial \| Real estate – mortgage – commercial and other
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 1,928,931	$ 1,787,022	1,723,598
Percentage	44.00%	42.00%
Real estate, mortgage \| Real estate – mortgage – residential (1-4 family) first mortgages
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 1,093,619	$ 1,054,176	1,038,436
Percentage	25.00%	25.00%
Real estate, mortgage \| Real estate – mortgage – home equity loans / lines of credit
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 343,378	$ 359,162	362,829
Percentage	8.00%	8.00%
Installment loans to individuals
Loans and Leases Receivable Disclosure [Line Items]
Loans	$ 70,962	$ 71,392	$ 70,096
Percentage	1.00%	2.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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