Short-Term Debt - Outstanding Balances of Short-Term Debt by Type of Collateral Securing Debt (Details)		3 Months Ended	12 Months Ended
		Mar. 31, 2023 USD ($) facility	Dec. 31, 2022 USD ($) facility
Short-term Debt [Line Items]
Outstanding Balance	[1]	$ 1,616,452,000	$ 2,029,679,000
Facilities
Short-term Debt [Line Items]
Number of Facilities | facility		18	19
Outstanding Balance		$ 1,253,277,000	$ 1,620,096,000
Facilities | Residential loan warehouse
Short-term Debt [Line Items]
Number of Facilities | facility		6	7
Outstanding Balance		$ 25,590,000	$ 703,406,000
Limit		$ 1,750,000,000	$ 2,550,000,000
Weighted Average Interest Rate (as a percent)		6.83%	6.16%
Weighted Average Days Until Maturity		229 days	267 days
Facilities | Business purpose loan warehouse
Short-term Debt [Line Items]
Number of Facilities | facility		4	4
Outstanding Balance		$ 777,067,000	$ 680,100,000
Limit		$ 1,650,000,000	$ 1,650,000,000
Weighted Average Interest Rate (as a percent)		7.31%	6.93%
Weighted Average Days Until Maturity		112 days	179 days
Facilities | Real estate securities repo
Short-term Debt [Line Items]
Number of Facilities | facility		7	7
Outstanding Balance		$ 325,549,000	$ 124,909,000
Limit		$ 0	$ 0
Weighted Average Interest Rate (as a percent)		6.11%	5.22%
Weighted Average Days Until Maturity		28 days	27 days
Facilities | HEI warehouse
Short-term Debt [Line Items]
Number of Facilities | facility		1	1
Outstanding Balance		$ 125,071,000	$ 111,681,000
Limit		$ 150,000,000	$ 150,000,000
Weighted Average Interest Rate (as a percent)		9.39%	8.54%
Weighted Average Days Until Maturity		216 days	306 days
Servicer advance financing
Short-term Debt [Line Items]
Number of Facilities | facility		1	1
Outstanding Balance		$ 197,883,000	$ 206,510,000
Limit		$ 290,000,000	$ 290,000,000
Weighted Average Interest Rate (as a percent)		7.04%	6.67%
Weighted Average Days Until Maturity		215 days	305 days
Promissory notes
Short-term Debt [Line Items]
Outstanding Balance		$ 21,808,000	$ 27,058,000
Weighted Average Interest Rate (as a percent)		6.76%	6.64%
Convertible notes, net
Short-term Debt [Line Items]
Outstanding Balance		$ 143,484,000	$ 176,015,000
Weighted Average Interest Rate (as a percent)		4.75%	4.75%
Weighted Average Days Until Maturity		137 days	227 days

[1] Our consolidated balance sheets include assets of consolidated variable interest entities (“VIEs”) that can only be used to settle obligations of these VIEs and liabilities of consolidated VIEs for which creditors do not have recourse to Redwood Trust, Inc. or its affiliates. At March 31, 2023 and December 31, 2022, assets of consolidated VIEs totaled $9,836,956 and $9,257,291, respectively. At March 31, 2023 and December 31, 2022, liabilities of consolidated VIEs totaled $8,729,585 and $8,270,276, respectively. See Note 4 for further discussion.