LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Loan Portfolio by Type of Loan (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Loans held for investment:
Total loans	$ 1,958,634	$ 1,706,395
Deferred loan (fees) costs, net	(3,643)	601
Allowance for credit losses	(33,757)	(16,202)	$ (16,394)	$ (14,651)
Total net loans	1,921,234	1,690,794
Commercial and industrial
Loans held for investment:
Total loans	531,152	279,583
Allowance for credit losses	(4,018)	(2,056)	(2,057)	(1,751)
Construction and development
Loans held for investment:
Total loans	269,101	280,498
Allowance for credit losses	(4,929)	(2,378)	(2,135)	(1,920)
Commercial real estate
Loans held for investment:
Total loans	602,664	567,360
Allowance for credit losses	(15,695)	(6,853)	(6,889)	(6,025)
Farmland
Loans held for investment:
Total loans	80,197	57,476
Allowance for credit losses	(1,290)	(570)	(594)	(643)
1-4 family residential
Loans held for investment:
Total loans	385,783	412,166
Allowance for credit losses	(6,185)	(3,125)	(3,077)	(2,868)
Multi-family residential
Loans held for investment:
Total loans	19,499	37,379
Allowance for credit losses	(325)	(409)	(830)	(631)
Consumer
Loans held for investment:
Total loans	52,855	53,245
Allowance for credit losses	(975)	(602)	(600)	(565)
Agricultural
Loans held for investment:
Total loans	17,004	18,359
Allowance for credit losses	(331)	(197)	(201)	(238)
Overdrafts
Loans held for investment:
Total loans	379	329
Allowance for credit losses	$ (9)	$ (12)	$ (11)	$ (10)

Loans and leases receivable deferred (fees) costs net.

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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 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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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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