Summary of Other Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Margin receivable	$ 55,926	$ 63,424
Investment receivable	12,076	153
Other pledged collateral	5,000
REO	3,965	4,245
Prepaid expenses	1,219	1,684
Fixed assets and leasehold improvements	859	494
Income tax receivables	306	4,762
Other	1,032	618
Total Other Assets	$ 80,383	$ 75,380