LOANS HELD FOR INVESTMENT AND ALLOWANCE FOR CREDIT LOSSES, (Narratives) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Jan. 01, 2020	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss	$ 21,083,000	$ 14,120,000	$ 13,905,000	$ 17,174,000	$ 14,210,000
Loans extended	1,841,304,000		1,822,024,000
Accrued interest receivable	5,700,000		5,500,000
Provision for credit losses	4,990,000
Net loan charge-offs	1,081,000
Interest income on nonaccrual loans	29,000
Nonaccrual loans	4,874,000		4,472,000
Real estate loans for which formal foreclosure proceedings were in process	600,000
TDRs	16,900,000		17,600,000
TDRs performing in accordance with modified terms	15,900,000		16,900,000
Estimated loan loss reserves	800,000		1,500,000
TDRs, for which there was a payment default and the loans were modified within the twelve months prior to default	100,000
Loan modified with a recorded investment	200,000	$ 100,000
Purchase of real estate secured adjustable rate loans	1,500,000
Adjustments related to Covid 19 [Member]
Financing Receivable, Allowance for Credit Loss	$ 3,900,000
Impact of Adoption of ASC 326 [Member]
Financing Receivable, Allowance for Credit Loss			$ 3,269,000