Principles of Consolidation - Additional Information (Detail) (Variable Interest Entity, Not Primary Beneficiary)	30 Months Ended
Jun. 30, 2014 Entity
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Number of securitization entities to which asset transferred	19

Number of Securitization Entities to which Asset Transferred

No definition available.

Name:	rwt_NumberOfSecuritizationEntitiesToWhichAssetTransferred
Namespace Prefix:	rwt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration