Fair Value - Reconciliation of Beginning and Ending Balances of Company's Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Parenthetical) (Detail) (Reverse Loans Held For Sale [Member], USD $)	Jun. 30, 2013	Dec. 31, 2012
Reverse Loans Held For Sale [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Assets, Fair Value	$ 0	$ 28,500,000