DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Derivative Assets and Liabilties (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Assets, at Fair Value	$ 8,231	$ 0
Liabilities, at Fair Value	33,229	20,658
Restricted cash	60,761	84,885
Securities Borrowed	139,843	0
Other Liabilities	1,712	1,041
Not Designated as Hedging Instrument, Economic Hedge [Member] \| Position [Domain]
Derivative [Line Items]
Assets, at Fair Value	8,231	0
Liabilities, at Fair Value	173,072	20,658
Restricted cash	24,422	19,034
Interest Rate Swap [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member] \| Position [Domain]
Derivative [Line Items]
Liabilities, at Fair Value	29,940	20,146
Restricted cash	23,149	17,450
TBA Contracts [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member] \| Position [Domain]
Derivative [Line Items]
Assets, at Fair Value	406	0
Liabilities, at Fair Value	0	512
Restricted cash	0	246
Other Liabilities	(730)	0
Eurodollar Future Margin [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member] \| Position [Domain]
Derivative [Line Items]
Restricted cash	655	1,338
Payer Swaption [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member] \| Position [Domain]
Derivative [Line Items]
Restricted cash	1,348	0
Payer Swaption [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative [Line Items]
Liabilities, at Fair Value	3,289	0
Payer Swaption [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member] \| Long [Member]
Derivative [Line Items]
Assets, at Fair Value	7,825	0
US Treasury Securities [Member] \| Not Designated as Hedging Instrument, Economic Hedge [Member]
Derivative [Line Items]
Securities Borrowed	$ 139,843	$ 0

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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