Principles of Consolidation - Mortgage Servicing Rights Assumptions Related to Unconsolidated Variable Interest Entity's Sponsored by Redwood (Detail)	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Subordinate Securities
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Credit loss assumptions	0.25%	0.25%	0.25%	0.25%
Senior Securities
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Credit loss assumptions	0.25%	0.25%	0.25%	0.25%
Variable Interest Entity, Not Primary Beneficiary \| Subordinate Securities
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Prepayment rate	8.00%	10.00%	8.00%	10.00%
Discount rates	6.00%	5.00%	6.00%	5.00%
Variable Interest Entity, Not Primary Beneficiary \| Senior Securities
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Prepayment rate	8.00%	10.00%	8.00%	10.00%
Discount rates	3.00%	3.00%	3.00%	3.00%
Variable Interest Entity, Not Primary Beneficiary \| Mortgage servicing rights
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Discount rates	11.00%	11.00%	11.00%	11.00%
Variable Interest Entity, Not Primary Beneficiary \| Mortgage servicing rights \| Minimum
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Prepayment rate	5.00%	5.00%	5.00%	5.00%
Variable Interest Entity, Not Primary Beneficiary \| Mortgage servicing rights \| Maximum
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Prepayment rate	13.00%	15.00%	15.00%	15.00%

Discount rate which is used to value residual cash flows generated by financial assets of the securitization, asset-backed financing arrangement, or similar transfer for initial fair value measurement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107207-111719

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- Definition

Rate at which principal will not be repaid on securitized financial assets, including for example, but not limited to, expected static pool losses for initial fair value measurement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107207-111719

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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

Estimated rate of prepayment of principal on financial assets for initial fair value measurement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107207-111719

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