INVESTMENTS IN SERVICER ADVANCES - Summary of Investments in Servicer Advances - Additional Information (Details) - USD ($) $ in Thousands		Sep. 30, 2015		Dec. 31, 2014
Investments in and Advances to Affiliates [Line Items]
Carrying Value		$ 7,499,775		$ 3,270,839
Face amount of debt		11,038,723
Servicer Advance Joint Venture [Member]
Investments in and Advances to Affiliates [Line Items]
Carrying Value	[1]	7,499,775	[2]	3,270,839
Servicer Advance Joint Venture [Member] | Servicer Advances [Member]
Investments in and Advances to Affiliates [Line Items]
Unpaid Principal Balance (“UPB”) of Underlying Mortgages	[3]	228,839,917		96,547,773
Carrying Value	[3]	$ 7,644,435		$ 3,102,492
Servicer Advances to UPB of Underlying Residential Mortgage Loans	[3]	3.30%		3.20%
Face amount of debt	[3]	$ 7,055,203		$ 2,890,230
Gross Loan-to-Value	[3],[4]	90.50%		91.40%
Net Loan-to-Value	[3],[4],[5]	89.40%		90.40%
Gross Cost of Funds	[3],[6]	3.10%		3.00%
Net Cost of Funds	[3],[6]	2.30%		2.30%

[1] Carrying value represents the fair value of the investments in servicer advances, including the basic fee component of the related MSRs.

[2] Excludes an asset-backed security collateralized by servicer advances purchased during the third quarter of 2015. This security had a face amount of $122.0 million and was purchased for $122.0 million. See Note 7 for details related to this security.

[3] The following types of advances comprise the investments in servicer advances: September 30, 2015December 31, 2014Principal and interest advances$2,376,186$729,713Escrow advances (taxes and insurance advances)3,653,3201,600,713Foreclosure advances1,614,929772,066Total$7,644,435 $3,102,492

[4] Based on outstanding servicer advances as of September 30, 2015, excluding purchased but unsettled servicer advances.

[5] Ratio of face amount of borrowings to par amount of servicer advance collateral, net of an interest reserve maintained by the Buyer.

[6] Annualized measure of the cost associated with borrowings. Gross Cost of Funds primarily includes interest expense and facility fees. Net Cost of Funds excludes facility fees.