LOANS HELD FOR INVESTMENT AND ALLOWANCE FOR CREDIT LOSSES (Activity in the allowance for credit losses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Activity in the allowance for loan losses by portfolio class
Beginning Balance			$ 13,905
Provision for Loan Losses		$ 646	6,995	$ 1,413
Charge-Offs		(865)		(2,226)
Recoveries		692		1,196
Net Charge-Offs		(173)		(1,030)
Ending Balance	$ 22,457	14,593	22,457	14,593
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	21,083	14,120	13,905	14,210
Provision for credit losses	1,615		6,605
Charge-Offs	(1,414)		(3,494)
Recoveries	1,173		2,172
Net Charge-Offs	(241)		(1,322)
Ending Balance	22,457	14,593	22,457	14,593
Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			3,269
Commercial, Financial and Agricultural [Member]
Activity in the allowance for loan losses by portfolio class
Provision for Loan Losses		195		412
Charge-Offs		(235)		(330)
Recoveries		58		132
Net Charge-Offs		(177)		(198)
Ending Balance		1,648		1,648
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	2,247	1,630	1,675	1,434
Provision for credit losses	333		739
Charge-Offs	(186)		(548)
Recoveries	74		114
Net Charge-Offs	(112)		(434)
Ending Balance	2,468	1,648	2,468	1,648
Commercial, Financial and Agricultural [Member] | Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			488
Real Estate - Construction [Member]
Activity in the allowance for loan losses by portfolio class
Provision for Loan Losses		140		241
Charge-Offs		0		0
Recoveries		0		0
Net Charge-Offs		0		0
Ending Balance		521		521
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	1,239	381	370	280
Provision for credit losses	716		1,283
Charge-Offs	0		0
Recoveries	0		0
Net Charge-Offs	0		0
Ending Balance	1,955	521	1,955	521
Real Estate - Construction [Member] | Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			302
Real Estate - Commercial Mortgage [Member]
Activity in the allowance for loan losses by portfolio class
Provision for Loan Losses		(204)		(307)
Charge-Offs		0		(155)
Recoveries		100		170
Net Charge-Offs		100		15
Ending Balance		3,889		3,889
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	5,828	3,993	3,416	4,181
Provision for credit losses	742		1,516
Charge-Offs	0		(11)
Recoveries	70		261
Net Charge-Offs	70		250
Ending Balance	6,640	3,889	6,640	3,889
Real Estate - Commercial Mortgage [Member] | Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			1,458
Real Estate - Residential [Member]
Activity in the allowance for loan losses by portfolio class
Provision for Loan Losses		(134)		(128)
Charge-Offs		(65)		(329)
Recoveries		223		267
Net Charge-Offs		158		(62)
Ending Balance		3,210		3,210
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	6,005	3,186	3,128	3,400
Provision for credit losses	(615)		1,089
Charge-Offs	(1)		(111)
Recoveries	51		91
Net Charge-Offs	50		(20)
Ending Balance	5,440	3,210	5,440	3,210
Real Estate - Residential [Member] | Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			1,243
Real Estate - Home Equity [Member]
Activity in the allowance for loan losses by portfolio class
Provision for Loan Losses		107		87
Charge-Offs		(45)		(97)
Recoveries		60		92
Net Charge-Offs		15		(5)
Ending Balance		2,383		2,383
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	2,701	2,261	2,224	2,301
Provision for credit losses	40		141
Charge-Offs	(52)		(83)
Recoveries	64		97
Net Charge-Offs	12		14
Ending Balance	2,753	2,383	2,753	2,383
Real Estate - Home Equity [Member] | Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			374
Consumer [Member]
Activity in the allowance for loan losses by portfolio class
Provision for Loan Losses		542		1,108
Charge-Offs		(520)		(1,315)
Recoveries		251		535
Net Charge-Offs		(269)		(780)
Ending Balance		2,942		2,942
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	3,063	2,669	3,092	2,614
Provision for credit losses	399		1,837
Charge-Offs	(1,175)		(2,741)
Recoveries	914		1,609
Net Charge-Offs	(261)		(1,132)
Ending Balance	$ 3,201	$ 2,942	3,201	$ 2,942
Consumer [Member] | Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			$ (596)