Principles of Consolidation - Cash Flows Related to Unconsolidated Variable Interest Entity's Sponsored by Redwood (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Variable Interest Entity [Line Items]
Proceeds from new transfers	$ 376,126	$ 329,231	$ 1,138,778	$ 2,723,012
MSR fees received	2,919	3,405	9,084	10,216
Funding of compensating interest, net	(76)	(46)	(213)	(102)
Cash flows received on retained securities	$ 6,603	$ 7,267	$ 20,892	$ 21,720