Commitments and Contingencies - Additional Information (Details) $ in Thousands		3 Months Ended	12 Months Ended
		Dec. 31, 2018 partnership	Dec. 31, 2021 USD ($) lease loan repurchase_request	Dec. 31, 2020 USD ($) repurchase_request loan	Dec. 31, 2019 USD ($) loan	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Lessee, number of leases | lease			7
Present value of remaining lease payments			$ 24,454
Operating lease expense			4,000	$ 4,000	$ 3,000
Unamortized leasehold improvements			3,000
Leasehold amortization expense			$ 500	500	400
Number of new leases | lease			2
Lease liability			$ 20,960	$ 16,687
Operating Lease, Liability, Statement of Financial Position [Extensible List]			Accounts Payable and Accrued Liabilities	Accounts Payable and Accrued Liabilities
Operating lease right-of-use assets			$ 18,772	$ 15,012
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]			Other assets	Other assets
Weighted average remaining lease term			6 years
Discount rate (as a percent)			5.10%
Derivative liabilities	[1]		$ 3,317	$ 16,072
Net market valuation adjustments			321,433	(541,399)	97,006
Number of partnerships, committed to fund | partnership		2
Risk share income			2,815	4,367	$ 3,522
Guarantee obligations			7,459	10,039
Guarantee obligation, credit reserve			5,000
SPE, assets			34,000	46,000
SPE, liabilities			7,000	10,000
Residential loan and MSR repurchase reserve			$ 9,306	$ 8,631
Residential loans repurchase requests | repurchase_request			4	10
Residential loans, number of loans repurchased | loan			2	1	0
Residential loans repurchase provision (reversal)			$ 1,000	$ (4,000)	$ 100
Residential loans repurchased during period			200	100	0
Aggregate amount of loss contingency reserves			2,000
Residential Loan Seller Demands
Loss Contingencies [Line Items]
Expenses from litigation recorded				10,000
Aggregate amount of accrual			500
Residential Loans
Loss Contingencies [Line Items]
Unpaid principal balance			1,813,865	172,748
Loans, at fair value			1,845,282	176,641
Financing Receivables, Equal to Greater than 90 Days Past Due | Residential Loans
Loss Contingencies [Line Items]
Loans, at fair value			2,923	1,882
Mortgage Banking And Investment Activities
Loss Contingencies [Line Items]
Market valuation changes in fair value of guarantee asset			100	1,000	$ 200
Guarantee Obligations
Loss Contingencies [Line Items]
Original principal balance of loans sold subject to risk sharing agreement						$ 3,190,000	$ 3,190,000
Potential future payments on risk sharing agreements			44,000
Unpaid principal balance			$ 552,000
FICO credit score			756
Loan to value ratio			74.00%
Guarantee Obligations | Residential Loans
Loss Contingencies [Line Items]
Loans held as assets amount in foreclosure			$ 200
Guarantee Obligations | Financing Receivables, Equal to Greater than 90 Days Past Due
Loss Contingencies [Line Items]
Loans, at fair value			18,000
Commitment To Fund Residential Bridge Loan
Loss Contingencies [Line Items]
Commitments to fund temporary advances			625,000
Derivative liabilities			1,000	2,000
Net market valuation adjustments			1,000	$ (2,000)
Commitments To Fund Point Options
Loss Contingencies [Line Items]
Commitments to fund temporary advances			$ 94,000

[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 December 31, 2021 and 2020, assets of consolidated VIEs totaled $10,661,081 and $8,141,069, respectively. At December 31, 2021 and 2020, liabilities of consolidated VIEs totaled $9,619,347 and $7,148,414, respectively. See Note 4 for further discussion.