DERIVATIVE FINANCIAL INTSTRUMENTS - Summary of Outstanding Swaptions (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Assets, at Fair Value	$ 16,885,000	$ 17,160,000
Payer Swaption [Member] | Less Than Or Equal To One Year [Member]
Derivatives, Fair Value [Line Items]
Swaption Cost	7,805,000	2,367,000
Assets, at Fair Value	$ 123,000	$ 3,405,000
Derivative Instruments Average Months To Expiration	1 month 14 days	8 months
Notional Amount	$ 700,000,000	$ 200,000,000
Derivative Average Fixed Interest Rate	3.20%	2.16%
Term (Years)	9 years	6 years