INVESTMENTS IN REAL ESTATE SECURITIES - Narrative (Details)				3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 25, 2015 USD ($) loan	Jun. 25, 2015 USD ($) loan	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairment (OTTI)				$ 1,574,000	$ 0	$ 3,294,000	$ 943,000
Real estate securities acquired during the period with credit quality deterioration, face amount						280,200,000
Real estate securities acquired during the period with credit quality deterioration, expected cash flows						323,000,000
Real estate securities acquired during the period with credit quality deterioration, fair value						205,800,000
Non-Agency RMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of trusts | loan		7	18
Outstanding Face Amount		$ 7,400,000.0	$ 13,700,000.0
Amortized cost basis of loans		$ 4,500,000	$ 9,100,000
Face amount of securities sold						441,100,000
Face amount of securities purchased						1,250,900,000
Sale Price of Securities Sold						389,700,000
Purchase Price of Securities Purchased						778,100,000
Agency RMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Face amount of securities sold	$ 1,900,000,000					4,278,500,000
Face amount of securities purchased	1,000,000,000					3,936,100,000
Sale Price of Securities Sold	2,000,000,000					4,466,700,000
Purchase Price of Securities Purchased	$ 1,100,000,000					$ 4,085,700,000