DERIVATIVES - Schedule of Derivatives - Notional Amount (Details) - Not Designated as Hedging Instrument [Member] - USD ($)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Short [Member]
Derivative [Line Items]
Derivative liability, notional amount		$ 3,500,000,000
Long [Member]
Derivative [Line Items]
Derivative liability, notional amount		2,100,000,000
TBAs [Member] | Short [Member]
Derivative [Line Items]
Derivative liability, notional amount	[1]	3,465,500,000	$ 1,450,000,000
TBAs [Member] | Long [Member]
Derivative [Line Items]
Derivative liability, notional amount	[1]	2,125,552,000	750,000,000
Interest Rate Caps [Member]
Derivative [Line Items]
Derivative asset, notional amount	[2]	$ 1,185,000,000	3,400,000,000
Average remaining maturity (in months)		18 months
Interest Rate Swaps [Member]
Derivative [Line Items]
Derivative liability, notional amount	[3]	$ 3,640,000,000	$ 2,444,000,000
Average remaining maturity (in months)		22 months
Average fixed interest rate		1.35%
Interest Rate Cap, Contract One [Member]
Derivative [Line Items]
Derivative, cap interest rate		0.50%
Notional amount of derivatives		$ 550,000,000
Interest Rate Cap, Contract Two [Member]
Derivative [Line Items]
Derivative, cap interest rate		0.75%
Notional amount of derivatives		$ 300,000,000
Interest Rate Cap, Contract Three [Member]
Derivative [Line Items]
Derivative, cap interest rate		2.00%
Notional amount of derivatives		$ 185,000,000
Interest Rate Cap, Contract Four [Member]
Derivative [Line Items]
Derivative, cap interest rate		4.00%
Notional amount of derivatives		$ 150,000,000

[1] Represents the notional amount of Agency RMBS, classified as derivatives.

[2] Caps LIBOR at 0.50% for $550.0 million of notional, at 0.75% for $300.0 million of notional, at 2.00% for $185.0 million of notional, and at 4.00% for $150.0 million of notional. The weighted average maturity of the interest rate caps as of December 31, 2016 was 18 months.

[3] Receive LIBOR and pay a fixed rate. The weighted average maturity of the interest rate swaps as of December 31, 2016 was 22 months and the weighted average fixed pay rate was 1.35%.