DEBT OBLIGATIONS - Schedule of Debt Obligations - Carrying Value (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Debt Instrument [Roll Forward]
Beginning balance	$ 6,062,299	[1]
Borrowings	1,121,121		1,618,664
Modified retrospective adjustment for the adoption of ASU No. 2014-11	2,310
Repayments	(2,016,777)		(1,080,197)
Ending balance	5,338,807
Servicer Advances [Member]
Debt Instrument [Roll Forward]
Beginning balance				2,890,230	[1]
Ending balance	2,875,412			2,890,230	[1]
Real Estate Securities [Member]
Debt Instrument [Roll Forward]
Beginning balance				2,246,651	[1]
Ending balance	1,928,891			2,246,651	[1]
Real Estate Loans [Member]
Debt Instrument [Roll Forward]
Beginning balance				925,418	[1]
Ending balance	434,504			925,418	[1]
Other [Member]
Debt Instrument [Roll Forward]
Beginning balance				0	[1]
Ending balance	100,000			0	[1]
Repurchase Agreements [Member]
Debt Instrument [Roll Forward]
Borrowings	1,121,121
Repayments	(2,016,777)
Repurchase Agreements [Member] | Servicer Advances [Member]
Debt Instrument [Roll Forward]
Borrowings	0
Repayments	0
Repurchase Agreements [Member] | Real Estate Securities [Member]
Debt Instrument [Roll Forward]
Borrowings	1,089,257
Repayments	(1,491,666)
Repurchase Agreements [Member] | Real Estate Loans [Member]
Debt Instrument [Roll Forward]
Borrowings	31,864
Repayments	(525,111)
Repurchase Agreements [Member] | Other [Member]
Debt Instrument [Roll Forward]
Borrowings	0
Repayments	0
Notes Payable [Member]
Debt Instrument [Roll Forward]
Borrowings	482,334
Repayments	(396,125)
Notes Payable [Member] | Servicer Advances [Member]
Debt Instrument [Roll Forward]
Borrowings	380,702
Repayments	(395,520)
Notes Payable [Member] | Real Estate Securities [Member]
Debt Instrument [Roll Forward]
Borrowings	0
Repayments	0
Notes Payable [Member] | Real Estate Loans [Member]
Debt Instrument [Roll Forward]
Borrowings	1,632
Repayments	(605)
Notes Payable [Member] | Other [Member]
Debt Instrument [Roll Forward]
Borrowings	100,000
Repayments	0
Accounting Standards Update 2014-11 [Member]
Debt Instrument [Roll Forward]
Modified retrospective adjustment for the adoption of ASU No. 2014-11	85,955		0
Accounting Standards Update 2014-11 [Member] | Repurchase Agreements [Member]
Debt Instrument [Roll Forward]
Modified retrospective adjustment for the adoption of ASU No. 2014-11	85,955
Accounting Standards Update 2014-11 [Member] | Repurchase Agreements [Member] | Servicer Advances [Member]
Debt Instrument [Roll Forward]
Modified retrospective adjustment for the adoption of ASU No. 2014-11	0
Accounting Standards Update 2014-11 [Member] | Repurchase Agreements [Member] | Real Estate Securities [Member]
Debt Instrument [Roll Forward]
Modified retrospective adjustment for the adoption of ASU No. 2014-11	84,649
Accounting Standards Update 2014-11 [Member] | Repurchase Agreements [Member] | Real Estate Loans [Member]
Debt Instrument [Roll Forward]
Modified retrospective adjustment for the adoption of ASU No. 2014-11	1,306
Accounting Standards Update 2014-11 [Member] | Repurchase Agreements [Member] | Other [Member]
Debt Instrument [Roll Forward]
Modified retrospective adjustment for the adoption of ASU No. 2014-11	$ 0

[1] Excludes debt related to linked transactions (Note 10).