LOANS HELD-FOR-INVESTMENT (Activity) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Loans Held-for-Investment [Roll Forward]
Beginning Balance, Principal Balance	$ 300,135,000
Beginning Balance, Deferred Fees/Other Items	6,047,000
Beginning Balance, Loan Fees Receivable	7,542,000
Beginning Balance, Net Book Value	301,630,000
Loan originations and acquisitions, Principal Balance	697,127,000
Loan originations and acquisitions, Deferred Fees/Other items	(5,000)
Loan originations and acquisitions, Loan Fees Receivable	5,000
Loan originations and acquisitions, Net Book Value	697,127,000
Cure payments receivable	6,411,000
Sale of loans, Principal Balance	(27,344,000)
Sale of loans, Deferred Fees/Other Items	945,000
Sale of loans, Net Book Value	(26,399,000)
Principal repayments received	(80,263,000)
Capitalized interest	539,000
Deferred fees and other items, Deferred Fees/Other Items	7,760,000
Deferred fees and other items, Loan Fees Receivable	(380,000)
Deferred fees and other items, Net Book Value	(8,140,000)
Accretion and amortization of fees and other items	1,990,000
Allowance for credit losses	(35,039,000)	$ (27,684,000)	$ (19,779,000)	$ 0
Ending Balance, Principal Balance	896,605,000
Ending Balance, Deferred Fees/Other Items	45,916,000
Ending Balance, Loan Fees Receivable	7,167,000
Ending Balance, Net Book Value	857,856,000
Senior loan
Loans Held-for-Investment [Roll Forward]
Repayments of debt	$ 40,800,000