Fair Value of Financial Instruments - Carrying Values and Estimated Fair Values of Assets and Liabilities (Details) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Assets
Real estate securities		$ 125,667	$ 860,540
Derivative assets	[1]	53,238	35,701
Pledged collateral		1,177	32,945
Liabilities
Contingent consideration		0	28,484
Derivative liabilities	[1]	16,072	163,424
Fair value		6,900,362	10,515,475
Shared Home Appreciation Options
Assets
Shared home appreciation options		42,440	45,085
Residential Loans
Assets
MSR Fair Value		231,489	169,204
Carrying Value
Assets
Real estate securities		344,125	1,099,874
Shared home appreciation options			45,085
Cash and cash equivalents		461,260	196,966
Restricted cash		83,190	93,867
Derivative assets		53,238	35,701
Margin receivable		4,758	209,776
FHLBC stock		5,000	43,393
Pledged collateral		1,177	32,945
Liabilities
Margin payable		0	1,700
Guarantee obligation		10,039	14,009
Contingent consideration		0	28,484
Derivative liabilities		16,072	163,424
Fair value		6,900,362	10,515,475
Amortized cost		200,299	0
FHLBC long-term borrowings		1,000	1,999,999
Other long-term debt, net		774,726	183,520
Convertible notes, net		511,085	631,125
Trust preferred securities and subordinated notes, net		138,674	138,628
Carrying Value | Servicer advance investments
Assets
MSR Fair Value		231,489	169,204
Carrying Value | MSRs
Assets
MSR Fair Value		8,815	42,224
Carrying Value | Excess MSRs
Assets
Other assets		34,418	31,814
Carrying Value | REO
Assets
Other assets		8,413	9,462
Carrying Value | Credit facilities
Liabilities
Short-term debt		522,609	2,329,145
Carrying Value | Residential Loans | Residential loans, held-for-sale at fair value
Assets
Loans, held-for-sale		176,604	536,280
Carrying Value | Residential Loans | Residential loans, held-for-investment
Assets
Loans, held-for-investment		4,072,410	7,178,465
Carrying Value | Residential Loans | Business purpose loans, held-for-sale
Assets
Loans, held-for-sale		245,394	331,565
Carrying Value | Residential Loans | Business purpose loans, held-for-investment, at fair value
Assets
Loans, held-for-investment		3,890,959	3,175,178
Carrying Value | Residential Loans | Multifamily securities
Assets
Loans, held-for-investment		492,221	4,408,524
Fair Value
Assets
Real estate securities		344,125	1,099,874
Shared home appreciation options		42,440	45,085
Cash and cash equivalents		461,260	196,966
Restricted cash		83,190	93,867
Derivative assets		53,238	35,701
Margin receivable		4,758	209,776
FHLBC stock		5,000	43,393
Pledged collateral		1,177	32,945
Liabilities
Margin payable		0	1,700
Guarantee obligation		7,843	13,754
Contingent consideration		0	28,484
Derivative liabilities		16,072	163,424
Fair value		6,900,362	10,515,475
Amortized cost		204,892	0
FHLBC long-term borrowings		1,000	1,999,999
Other long-term debt, net		783,570	184,666
Convertible notes, net		499,865	661,985
Trust preferred securities and subordinated notes, net		80,910	99,045
Fair Value | Servicer advance investments
Assets
MSR Fair Value		231,489	169,204
Fair Value | MSRs
Assets
MSR Fair Value		8,815	42,224
Fair Value | Excess MSRs
Assets
Other assets		34,418	31,814
Fair Value | REO
Assets
Other assets		9,229	10,389
Fair Value | Credit facilities
Liabilities
Short-term debt		522,609	2,329,145
Fair Value | Residential Loans | Residential loans, held-for-sale at fair value
Assets
Loans, held-for-sale		176,604	536,280
Fair Value | Residential Loans | Residential loans, held-for-investment
Assets
Loans, held-for-investment		4,072,410	7,178,465
Fair Value | Residential Loans | Business purpose loans, held-for-sale
Assets
Loans, held-for-sale		245,394	331,565
Fair Value | Residential Loans | Business purpose loans, held-for-investment, at fair value
Assets
Loans, held-for-investment		3,890,959	3,175,178
Fair Value | Residential Loans | Multifamily securities
Assets
Loans, held-for-investment		$ 492,221	$ 4,408,524

[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, 2020 and December 31, 2019, assets of consolidated VIEs totaled $8,141,069 and $11,931,869, respectively. At December 31, 2020 and December 31, 2019, liabilities of consolidated VIEs totaled $7,148,414 and $10,717,072, respectively. See Note 4 for further discussion.