Residential Loans at Fair Value - Reconciliation of Changes in Residential Loans Held for Sale to Amounts Presented on Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
Feb. 09, 2018	Dec. 31, 2018	Dec. 31, 2017
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance at beginning of the period	$ 588,553	$ 371,282	$ 1,176,280
Purchases and originations of residential loans held for sale	1,207,155	11,821,103	16,128,212
Proceeds from sales of and payments on loans held for sale	(1,421,102)	(11,441,044)	(16,957,389)
Realized gains (losses) on sales of loans	3,582	(5,602)	171,537
Change in unrealized gains (losses) on loans held for sale	(9,343)	7,425	10,309
Interest income	2,298	23,790	34,126
Loans acquired from Non-Residual Trusts	0	0	25,062
Other	139	333	416
Balance at end of the period	$ 371,282	$ 777,287	$ 588,553

Loans receivable held for sale reconciliation to cash flow other period increase decrease.

No definition available.

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- Definition

The increase (decrease) during the reporting period in the value of mortgage loans that are held with the intention to sell or be securitized in the near future.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585

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- Definition

Interest and fee income from mortgage loans considered to be held-for-sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.1)
-URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260

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- Definition

The face amount of loans that will be sold to other entities.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount, after allowance for bad debt, of additions to loan receivables held-for-sale that are not part of a disposal group.

+ References

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- Definition

The aggregate amount of cash outflow for loans purchased and created with the intention to resell them in the near future.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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- Definition

The cash inflow from sales of loans that are secured with real estate mortgages and are held with the intention to resell in the near future.

+ References

+ Details

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- Definition

Reflects, by transferred financial asset type, the amount of sales proceeds in excess of or deficient from the sum of the carrying amounts of transferred financial assets plus transaction costs, including those transactions in which the seller/transferor has continuing involvement with the financial assets that have been transferred.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 40
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