Loans Originated for commercial real estate.

Name:	rwt_LoansOriginatedCommercialRealEstate
Namespace Prefix:	rwt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number Of Loans Originated Or Acquired

+ Details

Name:	rwt_NumberOfLoansOriginatedOrAcquired
Namespace Prefix:	rwt
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage Of Loan Premiums Amortized

+ Details

Name:	rwt_PercentageOfLoanPremiumsAmortized
Namespace Prefix:	rwt
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage Of Loans Prepaid

+ Details

Name:	rwt_PercentageOfLoansPrepaid
Namespace Prefix:	rwt
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Reflects the aggregate carrying amount of all commercial loans and leases held in portfolio, net of unearned income and the allowance for losses on commercial loans and leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5066-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 01-6
-Paragraph 13
-Subparagraph e
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6965416&loc=d3e5074-111524

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6375948&loc=d3e4428-111522

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetReportedAmountCommercial
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the aggregate carrying amount of all consumer loans and leases held in portfolio, net of unearned income and the allowance for losses on consumer loans and leases.

+ References

+ Details

Name:	us-gaap_LoansAndLeasesReceivableNetReportedAmountConsumer
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of the contractual principal due at the origination of the mortgage loan (face amount).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph c
-Subparagraph Schedule IV
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 29
-Article 12

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=6882300&loc=d3e5864-122674

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateFaceAmountOfMortgages
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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.

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Indicates the number of mortgages under each classification.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29.3)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph c
-Subparagraph Schedule IV
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 29
-Paragraph 3

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=6882300&loc=d3e5864-122674

+ Details

Name:	us-gaap_MortgageLoansOnRealEstateNumberOfLoans
Namespace Prefix:	us-gaap
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with purchasing loans held for investment purposes during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 102
-Paragraph 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 95
-Paragraph 17
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3213-108585

+ Details

Name:	us-gaap_PaymentsToAcquireLoansHeldForInvestment
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Reflects the cumulative amount of fees paid by borrowers which have not yet been taken into income and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 91
-Paragraph 21
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

+ Details

Name:	us-gaap_UnamortizedLoanCommitmentAndOriginationFeesAndUnamortizedDiscountsOrPremiums
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Real Estate Loans - Additional Information (Detail) (USD $)			6 Months Ended	12 Months Ended	6 Months Ended				6 Months Ended		6 Months Ended		6 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2011 Residential Real Estate Loans Held For Sale Contract	Dec. 31, 2010 Residential Real Estate Loans Held For Sale Contract	Jun. 30, 2011 Sequoia Residential Real Estate Loans Held for Investment	Dec. 31, 2010 Sequoia Residential Real Estate Loans Held for Investment	Jun. 30, 2011 Residential Real Estate Loans Held for Investment	Dec. 31, 2010 Residential Real Estate Loans Held for Investment	Jun. 30, 2011 Residential Real Estate Loans Held for Investment Residential Loans Acquired Prior To July 1st 2004	Dec. 31, 2010 Residential Real Estate Loans Held for Investment Residential Loans Acquired Prior To July 1st 2004	Jun. 30, 2011 Residential Real Estate Loans Held for Investment Residential Loans Acquired After July 1st 2004	Dec. 31, 2010 Residential Real Estate Loans Held for Investment Residential Loans Acquired After July 1st 2004	Jun. 30, 2011 Commercial Real Estate Loans at Fair Value Contract	Dec. 31, 2010 Commercial Real Estate Loans at Fair Value Contract	Jun. 30, 2011 Commercial Real Estate Loans Held For Investment Contract	Dec. 31, 2010 Commercial Real Estate Loans Held For Investment Contract	Jun. 30, 2011 Sequoia	Dec. 31, 2010 Sequoia
Mortgage Loans on Real Estate [Line Items]
Loans originated or acquired, principal value															$ 29,000,000
Number of loans			11	11									3	4	9	4
Number of loans originated or acquired															3
Principal value			3,000,000	3,000,000			3,882,603,000	3,815,273,000	1,600,000,000	1,700,000,000	2,300,000,000	2,100,000,000	14,000,000	23,000,000	72,000,000	31,000,000
Commercial real estate loans	83,866,000	50,386,000											12,698,000	19,850,000	71,168,000	30,536,000
Unamortized premium, net							38,100,000	42,399,000	25,000,000	28,000,000	13,000,000	15,000,000
Residential real estate loans	3,860,233,000	3,797,095,000	1,836,000	1,855,000	3,654,932,000	3,542,159,000	3,858,397,000	3,795,240,000									3,654,932,000	3,542,159,000
Percentage of loans prepaid									4.00%		5.00%
Percentage of premiums amortized									9.00%		7.00%
Amount paid to purchase prime quality residential loans					$ 254,000,000