Residential Mortgage Loans Held-For-Securitization - Summary of Residential Mortgage Loans Held-for-Investment (Detail) - Residential Mortgage Backed Securities $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2020 USD ($) loan	Dec. 31, 2019 USD ($) loan
Portfolio Characteristics:
Number of loans \| loan	261	300
Current principal balance	$ 127,782	$ 148,908
Average loan balance	$ 490	$ 496
Net weighted average coupon rate	5.39%	5.40%
Weighted average FICO score	742	744
Performance:
Current	$ 99,974	$ 146,999
Total	$ 127,782	$ 148,908
LTV
Portfolio Characteristics:
Weighted average LTV (loan-to-value)	70.00%	70.00%
DTI
Portfolio Characteristics:
Weighted average DTI (debt-to-income)	38.00%	38.00%
30 days delinquent
Performance:
Delinquent	$ 1,547	$ 1,909
60 days delinquent
Performance:
Delinquent	13,252
90+ days delinquent
Performance:
Delinquent	$ 13,009
12-months bank statements
Portfolio Characteristics:
Number of loans \| loan	12	17
24-months bank statements
Portfolio Characteristics:
Number of loans \| loan	49	56
Alt documentation
Portfolio Characteristics:
Number of loans \| loan	79	97
Full documentation
Portfolio Characteristics:
Number of loans \| loan	12	15
Written Verification of Employment
Portfolio Characteristics:
Number of loans \| loan	109	115

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Interest rate of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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