Fair Values - Schedule of Details of Carrying Amount, Face Amount, and Approximate Fair Value of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financial assets:
Loans receivable, net	$ 117,549
Financial liabilities:
Repurchase obligations	165,200
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	59,746	15,423
Restricted cash	21,972	14,246
Loans receivable, net	830,101	141,500
Financial liabilities:
Secured notes	8,848	8,497
Repurchase obligations	165,239
Securitized debt obligations	74,472	139,184
Face Amount [Member]
Financial assets:
Cash and cash equivalents	59,746	15,423
Restricted cash	21,972	14,246
Loans receivable, net	851,716	164,180
Financial liabilities:
Secured notes	8,848	8,497
Repurchase obligations	165,239
Securitized debt obligations	74,472	139,184
Fair Value [Member]
Financial assets:
Cash and cash equivalents	59,746	15,423
Restricted cash	21,972	14,246
Loans receivable, net	827,152	133,682
Financial liabilities:
Secured notes	7,827	7,374
Repurchase obligations	165,239
Securitized debt obligations	$ 51,454	$ 89,880