Use of Special Purpose Entities and Variable Interest Entities (Details) (USD $)	1 Months Ended	12 Months Ended				1 Months Ended
	Oct. 31, 2010	Dec. 31, 2011		Dec. 31, 2010		Jun. 30, 2011 CSMC Series 2011-7R	Jun. 30, 2011 CSMC Series 2011-7R Senior-support certificates	Jun. 30, 2011 CSMC Series 2011-7R Non-rated senior support certificates Class	Jun. 30, 2011 CSMC Series 2011-7R Non-rated interest only senior certificates	Feb. 28, 2011 CSMC Series 2011-1R	Feb. 28, 2011 CSMC Series 2011-1R Non-rated senior support certificates Class	Feb. 28, 2011 CSMC Series 2011-1R Non-rated interest only senior 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 Non-rated interest only senior certificates	Oct. 31, 2010 Deutsche Mortgage Securities, Inc. Real Estate Mortgage Investment Conduit Trust, Series 2010-RS2 Mezzanine Non-Agency MBS with S and P ratings Class	Oct. 31, 2010 Deutsche Mortgage Securities, Inc. Real Estate Mortgage Investment Conduit Trust, Series 2010-RS2 Non-rated subordinate Non-Agency MBS
Special purpose entities and variable interest entities
Principal value of Non-Agency MBS sold as part of the resecuritization transaction	$ 985,200,000					$ 1,283,000,000				$ 1,320,000,000
Variable interest rate, maximum (as a percent)						10.00%
Face amount of instrument issued						474,900,000				488,400,000			246,300,000
Reference rate to discount contractual cash flows						one-month LIBOR				one-month LIBOR			one-month LIBOR
Interest rate added to base rate (as a percent)						1.25%				1.00%			1.25%
Face amount of investment acquired								808,600,000			831,600,000				374,400,000	364,500,000
Number of classes of investment acquired								3			3				6
Proceeds from issuance of securitized debt		963,255,000		246,307,000			474,900,000			488,400,000			246,300,000
Notional amount of investment acquired									474,900,000			488,400,000		246,300,000
Non-Agency MBS transferred to consolidated variable interest entities ("VIEs")		2,283,070,000	[1]	705,704,000	[1]
Securitized debt		$ 875,520,000	[2]	$ 220,933,000	[2]

[1] Non-Agency MBS transferred to consolidated VIEs included in the consolidated balance sheet at December 31, 2011 and December 31, 2010 represent assets of consolidated VIEs that can be used only to settle the obligations of each respective VIE.

[2] Securitized Debt included in the consolidated balance sheet at December 31, 2011 and December 31, 2010, represents third-party liabilities of consolidated VIEs and excludes liabilities of the VIEs acquired by the Company that eliminate on consolidation. The third-party beneficial interest holders in the VIEs have no recourse to the general credit of the Company. (See Notes 9 and 14 for further discussion.)