Summary of Other Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Margin receivable	$ 46,970	$ 63,424
Investment receivable	1,821	153
Other pledged collateral	5,000
REO	4,050	4,245
Prepaid expenses	2,206	1,684
Fixed assets and leasehold improvements	1,065	494
Income tax receivables	895	4,762
Other	1,080	618
Total Other Assets	$ 63,087	$ 75,380