Residential Loans, Net - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Residential Loan Transfers Line Items
Minimum period after which past due residential loans are placed on non-accrual status		90 days
Minimum duration for past due residential loans to be considered as non-performing	30 days
Residential Loans [Member]
Residential Loan Transfers Line Items
Residential loans acquired to be held for investment	$ 462.2	$ 1,300.0
Residential loans originated to be held for investment	$ 338.0	$ 608.1