Credit Quality of Loans and Allowance for Loan Losses - Loan Portfolio and Concentrations (Details) $ in Thousands	9 Months Ended
Sep. 30, 2015 USD ($) industry_concentration	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)
Loan portfolio [Abstract]
Loans	$ 1,301,452	$ 1,284,431	$ 1,248,373
Less allowance for loan losses	(18,939)	(11,226)
Loans, net	$ 1,282,513	1,273,205
Number of industry segment concentration above threshold limit \| industry_concentration	1
Concentration risk, percentage	10.00%
Loans exposure in oil and gas industry	$ 295,600
Exposure in the oil and gas industry specified as percentage of total loans	22.70%
Loans with exposure in commercial real estate	$ 529,000
Loans on nonaccrual status	51,616	10,701
Commercial, financial and agricultural
Loan portfolio [Abstract]
Loans	482,452	467,147	452,065
Loans on nonaccrual status	29,171	2,642
Real estate - construction
Loan portfolio [Abstract]
Loans	74,279	68,577	86,315
Real estate – commercial
Loan portfolio [Abstract]
Loans	$ 473,319	467,172	430,930
Percentage of CRE loans secured by owner-occupied commercial properties	53.00%
Loans on nonaccrual status	$ 20,000
Nonaccrual status of loans specified as percentage of total CRE loans	3.80%
Real estate – residential
Loan portfolio [Abstract]
Loans	$ 151,667	154,602	153,915
Installment loans to individuals
Loan portfolio [Abstract]
Loans	113,199	119,328	116,340
Lease financing receivable
Loan portfolio [Abstract]
Loans	4,790	4,857	5,285
Loans on nonaccrual status	0	0
Other
Loan portfolio [Abstract]
Loans	1,746	2,748	$ 3,523
Loans on nonaccrual status	$ 0	$ 0

This line item represents the exposure in the oil and gas industry specified as a percentage of total loans.

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This line item represents the loans exposure in the oil and gas industry.

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This line item represents the loans with exposure in the commercial real estate section.

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This line item represents the percentage of nonaccrual status of loans specified as percentage of total CRE loans.

+ References

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This line item represents the number of industry segment concentration above threshold limit of the loan portfolio.

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This line item represents the percentage of CRE loans secured by owner occupied commercial properties.

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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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-Publisher FASB

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Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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