INVESTMENTS IN REAL ESTATE SECURITIES - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule of Available-for-sale Securities [Line Items]
Other-than-temporary impairment		$ 2,819	$ 649	$ 6,073	$ 1,720
Real estate securities acquired during the period with credit quality deterioration, face amount				1,765,100
Real estate securities acquired during the period with credit quality deterioration, expected cash flows				1,314,000
Real estate securities acquired during the period with credit quality deterioration, fair value				1,096,400
Agency RMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Face amount of securities sold	$ 1,500,000			3,089,800
Face amount of securities purchased	1,500,000			3,871,700
Sale price of securities sold	1,500,000			3,236,700
Purchase price of securities purchased	1,500,000			4,048,300
Non-Agency RMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Face amount of securities sold				129,800
Face amount of securities purchased	100,000			2,671,500
Sale price of securities sold				100,400
Purchase price of securities purchased	$ 100,000			$ 1,429,700