Carrying Value and Estimated Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
Financial Assets:
Residential mortgage loans held-for-investment through consolidated securitization trusts	[1]	$ 483,648	$ 549,016
Residential mortgage loans held-for-investment, Estimated Fair Value		489,090	538,362
Residential mortgage loans held-for-securitization		129,014	11,660
Residential mortgage loans held-for-securitization, Estimated Fair Value		131,361	11,660
Financial Liabilities:
Asset-backed securities issued by securitization trusts	[1]	474,285	539,651
Asset-backed securities issued by securitization trust, Estimated Fair Value		$ 477,835	$ 528,045

[1] The consolidated balance sheets include assets of consolidated variable interest entities, or VIEs, that can only be used to settle obligations and liabilities of the VIEs for which creditors do not have recourse to the Company. At September 30, 2019 and December 31, 2018, total assets of the consolidated VIEs were $485 million and $551 million (including accrued interest receivable of $1.6 million and $1.8 million), respectively (which is recorded above in the line item entitled “Interest receivable”), and total liabilities were $476 million and $541 million (including accrued interest payable of $1.6 million and $1.7 million), respectively (which is recorded in the line item above entitled “Accrued interest payable”). Please refer to Note 5, “Variable Interest Entities,” for further discussion.