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Real Estate Securities - Summary of Significant Valuation Assumptions for Available for Sale Securities (Details) - Prime | 6 Months Ended
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Jun. 30, 2017
Minimum |
Schedule of Available-for-sale Securities [Line Items] |
Prepayment rates (as a percent) | 8.00%
Projected losses (as a percent) | 0.25%
Maximum |
Schedule of Available-for-sale Securities [Line Items] |
Prepayment rates (as a percent) | 18.00%
Projected losses (as a percent) | 8.00%

X
- Definition This item represents a significant valuation assumption on prepayment rates, represented as a percentage, which was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are not other-than-temporarily impaired. + References No definition available. + Details
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Namespace Prefix: | rwt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition This item represents the default rate of the underlying assets in the security that were considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are not other-than-temporarily impaired. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563 + Details
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Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- 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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- Details
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- Details
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- Details
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