EQUITY AND EARNINGS PER SHARE - Narrative (Details) $ / shares in Units, $ in Thousands							1 Months Ended				3 Months Ended		9 Months Ended		33 Months Ended
		Sep. 18, 2015 USD ($) $ / shares	May. 14, 2015 USD ($) $ / shares	Mar. 16, 2015 USD ($) $ / shares	Dec. 18, 2014 USD ($) $ / shares	Oct. 17, 2014 shares	Jul. 31, 2015 employee shares	Jun. 30, 2015 USD ($) employee $ / shares shares	Apr. 30, 2015 USD ($) employee $ / shares shares	Oct. 31, 2014	Sep. 30, 2015 $ / shares shares	Sep. 30, 2014 $ / shares shares	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($) $ / shares shares	Sep. 30, 2015 $ / shares shares	Dec. 31, 2014 shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Reverse stock split						0.5				0.5
Common stock outstanding, prior to stock split (in shares)						282,800,000
Common stock, shares outstanding (in shares)						141,400,000					230,458,866		230,458,866		230,458,866	141,434,905
Issuance of common stock | $								$ 442,600	$ 436,100				$ 882,166	$ 173,201
Fair value assumption, risk free rate								2.61%	2.02%
Fair value assumption, dividend yield								7.81%	6.71%
Fair value assumption, volatility								23.73%	24.04%
Fair value assumption term								10 years	10 years
Options exercised (in shares)	[1]														7,564,298
Dividend declared per share (in dollars per share) | $ / shares		$ 0.46	$ 0.45	$ 0.38	$ 0.38						$ 0.46	$ 0.35	$ 1.29	$ 1.2
Dividends | $		$ 106,000	$ 89,500	$ 53,700	$ 53,700								$ 249,277
Share price (in dollars per share) | $ / shares											$ 13.10		$ 13.10		$ 13.10
Dilutive Securities, Common Stock Equivalents, Number Of Shares Outstanding											759,667	2,955,021	2,821,758	3,158,619
Executive Officer [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of employees | employee								1	1
Former Employee Of Manager [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of employees | employee							1
Fortress [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Common stock, shares outstanding (in shares)											2,400,000		2,400,000		2,400,000
Common Stock [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Common stock issued in public offering (in shares)								27,900,000	29,213,020
Public offering share price (in dollars per share) | $ / shares								$ 15.88	$ 15.25
Options granted to purchase number of shares (in shares)								2,800,000	5,750,000
Fair value of options granted to purchase shares | $								$ 3,700	$ 8,900
Options exercised (in shares)								6,200,000
Aggregate shares in cashless exercise (in shares)								3,600,000
Common Stock [Member] | Executive Officer [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Common stock issued in public offering (in shares)								9,100	250,000
Common Stock [Member] | Former Employee Of Manager [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options exercised (in shares)							37,500
Aggregate shares in cashless exercise (in shares)							20,227

[1] Exercised by employees of Fortress, subsequent to their assignment, or by directors. The options exercised had an intrinsic value of $60.5 million.