Use of Special Purpose Entities and Variable Interest Entities (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended					1 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Dec. 31, 2011		Feb. 29, 2012 WFMLT Series 2012-RR1	Feb. 29, 2012 WFMLT Series 2012-RR1 Senior-support certificates	Feb. 28, 2011 CSMC Series 2011-1R	Feb. 28, 2011 CSMC Series 2011-1R Senior-support certificates	Oct. 31, 2010 Deutsche Mortgage Securities, Inc. Real Estate Mortgage Investment Conduit Trust, Series 2010-RS2	Oct. 31, 2010 Deutsche Mortgage Securities, Inc. Real Estate Mortgage Investment Conduit Trust, Series 2010-RS2 Senior-support certificates	Jun. 30, 2011 CSMC Series 2011-7R	Jun. 30, 2011 CSMC Series 2011-7R Senior-support certificates
Special purpose entities and variable interest entities
Principal value of Non-Agency MBS sold						$ 433,347		$ 1,319,969		$ 985,228		$ 1,283,422
Face amount of Senior Bonds issued by the VIE and purchased by 3rd party investors						186,691		488,389		246,307		474,866
Face amount of Senior Support Certificates received by the Company							246,656		831,580		738,921		808,556
Outstanding amount of Senior Bonds	749,471	[1]		875,520	[1]	155,125		266,632		52,525		275,189
Pass-through rate for Senior Bonds issued								One-month LIBOR		One-month LIBOR		One-month LIBOR
Pass-through rate for Senior Bonds issued (as a percent)						2.85%
Interest rate added to base rate (as a percent)								1.00%		1.25%		1.25%
Cash received	186,691		963,255			186,691		488,389		246,307		474,866
Notional amount acquired of non-rated, interest only senior certificates						186,691		488,389		246,307		474,866
Expenses incurred	3,415					1,814		3,527		3,562		3,230
Non-Agency MBS transferred to consolidated variable interest entities ("VIEs")	$ 2,655,129	[2]		$ 2,283,070	[2]

[1] Securitized Debt represents third-party liabilities of consolidated VIEs and excludes liabilities of the VIEs acquired by the Company that eliminate in consolidation. The third-party beneficial interest holders in the VIEs have no recourse to the general credit of the Company. (See Notes 10 and 15 for further discussion.)

[2] Non-Agency MBS transferred to consolidated VIEs represent assets of the consolidated VIEs that can be used only to settle the obligations of each respective VIE.