Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on Recurring Basis (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
ABS issued		6,900,362	10,515,475
Fair Value, Measurements, Recurring
Assets
Business purpose loans		4,136,353	3,506,743
Multifamily loans		492,221	4,408,524
Real estate securities		344,125	1,099,874
Servicer advance investments		231,489	169,204
MSR Fair Value		8,815	42,224
Excess MSRs		34,418	31,814
Shared home appreciation options		42,440	45,085
Derivative assets		53,238	35,701
Pledged collateral		1,177	32,945
FHLBC stock		5,000	43,393
Liabilities
Contingent consideration			28,484
Derivative liabilities		16,072	163,424
ABS issued		6,900,362	10,515,475
Fair Value, Measurements, Recurring | Residential Loans
Assets
Residential loans		4,249,014	7,714,745
Fair Value, Measurements, Recurring | Level 1
Assets
Business purpose loans		0	0
Multifamily loans		0	0
Real estate securities			0
Servicer advance investments		0	0
MSR Fair Value			0
Excess MSRs		0	0
Shared home appreciation options		0	0
Derivative assets		18,260	6,531
Pledged collateral		1,177	32,945
FHLBC stock		0	0
Liabilities
Contingent consideration			0
Derivative liabilities		15,495	13,368
ABS issued			0
Fair Value, Measurements, Recurring | Level 1 | Residential Loans
Assets
Residential loans			0
Fair Value, Measurements, Recurring | Level 2
Assets
Business purpose loans		0	0
Multifamily loans		0	0
Real estate securities			0
Servicer advance investments		0	0
MSR Fair Value			0
Excess MSRs		0	0
Shared home appreciation options		0	0
Derivative assets		19,951	19,020
Pledged collateral			0
FHLBC stock		5,000	43,393
Liabilities
Contingent consideration			0
Derivative liabilities		0	148,766
ABS issued			0
Fair Value, Measurements, Recurring | Level 2 | Residential Loans
Assets
Residential loans		0	0
Fair Value, Measurements, Recurring | Level 3
Assets
Business purpose loans		4,136,353	3,506,743
Multifamily loans		492,221	4,408,524
Real estate securities		344,125	1,099,874
Servicer advance investments		231,489	169,204
MSR Fair Value		8,815	42,224
Excess MSRs		34,418	31,814
Shared home appreciation options		42,440	45,085
Derivative assets		15,027	10,150
Pledged collateral			0
FHLBC stock			0
Liabilities
Contingent consideration			28,484
Derivative liabilities		577	1,290
ABS issued		6,900,362	10,515,475
Fair Value, Measurements, Recurring | Level 3 | Residential Loans
Assets
Residential loans		$ 4,249,014	$ 7,714,745

[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.