Carrying Values and Estimated Fair Values of Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Assets
Trading securities	$ 141,615		$ 33,172
Available-for-sale securities	1,172,690		1,075,581
Mortgage servicing rights	43,098		5,315
Derivative assets	43,341		2,972
Liabilities
Derivative liabilities	29,571		51,081
Carrying Value
Assets
Trading securities	141,615		33,172
Available-for-sale securities	1,172,690		1,075,581
Mortgage servicing rights	43,098		5,315
Cash and cash equivalents	207,694		81,080
Restricted cash	405		383
Accrued interest receivable	16,111		12,442
Derivative assets	43,341		2,972
REO	3,965	[1]	4,245	[1]
Margin receivable	55,926	[1]	63,424	[1]
Other collateral posted	5,000	[1]
Liabilities
Short-term debt	1,445,961		551,918
Accrued interest payable	8,682		4,592
Derivative liabilities	29,571		51,081
ABS issued	2,214,296		2,529,941
Commercial borrowings	16,591
Convertible notes	287,500
Other Long-term debt	139,500		139,500
Carrying Value | Residential Loans at Fair Value
Assets
Loans, held-for-sale	1,219,368		553,576
Carrying Value | Residential Loans at Lower of Cost or Fair Value
Assets
Loans, held-for-sale	1,730		9,082
Carrying Value | Residential Loans Held for Investment
Assets
Loans, held-for-investment	1,998,178		2,272,812
Carrying Value | Commercial Loans at Fair Value
Assets
Loans, held-for-sale	149,470
Carrying Value | Commercial Loans at Lower of Cost or Fair Value
Assets
Loans, held-for-sale			8,500
Carrying Value | Commercial Loans Held For Investment
Assets
Loans, held-for-investment	345,353		304,510
Fair Value
Assets
Trading securities	141,615		33,172
Available-for-sale securities	1,172,690		1,075,581
Mortgage servicing rights	43,098		5,315
Cash and cash equivalents	207,694		81,080
Restricted cash	405		383
Accrued interest receivable	16,111		12,442
Derivative assets	43,341		2,972
REO	4,971	[1]	5,540	[1]
Margin receivable	55,926	[1]	63,424	[1]
Other collateral posted	5,000	[1]
Liabilities
Short-term debt	1,445,961		551,918
Accrued interest payable	8,682		4,592
Derivative liabilities	29,571		51,081
ABS issued	1,991,401		2,372,971
Commercial borrowings	16,591
Convertible notes	283,547
Other Long-term debt	104,625		90,675
Fair Value | Residential Loans at Fair Value
Assets
Loans, held-for-sale	1,219,368		553,576
Fair Value | Residential Loans at Lower of Cost or Fair Value
Assets
Loans, held-for-sale	1,807		9,324
Fair Value | Residential Loans Held for Investment
Assets
Loans, held-for-investment	1,801,052		2,062,352
Fair Value | Commercial Loans at Fair Value
Assets
Loans, held-for-sale	149,470
Fair Value | Commercial Loans at Lower of Cost or Fair Value
Assets
Loans, held-for-sale			8,500
Fair Value | Commercial Loans Held For Investment
Assets
Loans, held-for-investment	$ 349,212		$ 309,547

[1] These assets are included in Other Assets on our consolidated balance sheets.