LOANS HELD-FOR-INVESTMENT (Statistics) (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($) loan	Dec. 31, 2019 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan	173
Net book value	$ 857,856	$ 301,630
Loans receivable with variable rate of interest	100.00%
CRE Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan	12	11
Principal balance	$ 473,834	$ 297,357
Net book value	$ 447,008	$ 298,880
Weighted-average interest rate	7.60%	8.90%
Weighted-average maximum years to maturity	2 years 6 months	2 years 10 months 24 days
Broadly Syndicated Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan	161	1
Principal balance	$ 422,771	$ 2,750
Net book value	$ 410,848	$ 2,750
Weighted-average interest rate	3.80%	4.50%
Weighted-average maximum years to maturity	4 years 9 months 18 days	5 years 2 months 12 days