Transfers of Residential Loans - Schedule of Continuing Involvement with Mortgage Loans Sold with Servicing Rights Retained (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Carrying Value of Net Assets Recorded on the Consolidated Balance Sheets	$ 348,784	$ 416,474
Unpaid Principal Balance of Sold Loans	28,461,158	36,274,449
Servicing Rights, Net [Member]
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Carrying Value of Net Assets Recorded on the Consolidated Balance Sheets	323,335	385,744
Servicer And Protective Advances, Net [Member]
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Carrying Value of Net Assets Recorded on the Consolidated Balance Sheets	25,449	30,762
Payables and Accrued Liabilities [Member]
Qualitative and Quantitative Information, Transferor's Continuing Involvement [Line Items]
Carrying Value of Net Assets Recorded on the Consolidated Balance Sheets	$ 0	$ (32)

Amount of liabilities related to transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction that continue to be recognized in the statement of financial position. Includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

No definition available.

+ Details

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Period Type:	instant

- Definition

Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109247956&loc=d3e107314-111719

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction that continue to be recognized in the statement of financial position. Includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=109247956&loc=d3e107314-111719

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