Debt Instrument, Asset Backed Securities Issued, Amortized Cost

No definition available.

Name:	rwt_DebtInstrumentAssetBackedSecuritiesIssuedAmortizedCost
Namespace Prefix:	rwt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Long Term Marketable Securities Maturities Term

+ References

No definition available.

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Balance Type:	na
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.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt discount.

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

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- Details

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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentSecondaryCategorizationAxis=rwt_MaturityOverFiveYearsMember
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Asset-Backed Securities Issued - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
VIE, ownership interest rate		80.00%
Variable Interest Entity, Primary Beneficiary \| Freddie Mac SLST
Debt Instrument [Line Items]
ABS issued, net, Amortized cost	$ 210,000,000
Asset-backed securities issued \| Freddie Mac SLST
Debt Instrument [Line Items]
Debt instrument, face amount		$ 179,000,000	$ 205,000,000
Asset-backed securities issued \| Variable Interest Entity, Primary Beneficiary
Debt Instrument [Line Items]
VIE, ownership interest rate	100.00%
Debt instrument, face amount		176,000,000
Unamortized debt discount		$ 3,000,000
Debt Instrument interest rate		4.75%
Asset-backed securities issued \| Contractual maturities of over five years
Debt Instrument [Line Items]
Contractual maturities of securities (in years)		5 years