LOANS HELD FOR INVESTMENT - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($) Loan
Receivables [Abstract]
Number of loans originated or co-originated | Loan	36
Number of loans repaid or sold | Loan	55
Total Commitment	$ 1,700.0
Loans held for investment	1,600.0
Amount funded	504.6
Amount of repayments	$ 263.4
Percentage of loans held for investment having LIBOR floors	89.30%
Weighted average floor (as a percent)	0.61%