Principles of Consolidation - Securitization Activity Related to Unconsolidated Variable Interest Entity's Sponsored by Redwood (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Variable Interest Entity [Line Items]
Principal balance of loans transferred	$ 0	$ 400,836	$ 1,573,703	$ 749,093
Trading securities retained, at fair value
Variable Interest Entity [Line Items]
Securities retained, at fair value	0	1,792	43,362	3,508
AFS securities retained, at fair value
Variable Interest Entity [Line Items]
Securities retained, at fair value	$ 0	$ 1,069	$ 3,198	$ 1,954