Residential Loans - Reconciliation of the changes in residential loans held for sale to the amounts presented in the consolidated statements of cash flows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Receivables [Abstract]
Balance at beginning of period	$ 278,474	$ 45,065
Purchases and originations of residential loans held for sale	4,848,332	5,281,349
Proceeds from sales of and payments on residential loans held for sale	(3,522,518)	(3,749,979)
Realized gains on sales of residential loans	75,918	84,226
Change in unrealized gains on residental loans held for sale	(15,897)	(2,271)
Interest income	8,473	9,261
Transfers from residential loans held for investment	43	5,183
Other	(8,610)	(8,619)
Balance at end of period	$ 1,664,215	$ 1,664,215