Principles of Consolidation - Assets and Liabilities of Consolidated Variable Interest Entity's (Details) $ in Thousands		Jun. 30, 2020 USD ($) investment	Dec. 31, 2019 USD ($) investment
Variable Interest Entity [Line Items]
Other investments	[1]	$ 429,840	$ 358,130
Cash and cash equivalents	[1]	528,612	196,966
Restricted cash	[1]	44,496	93,867
Accrued interest receivable		44,134	71,058
Other assets	[1]	171,586	419,321
Total Assets	[1]	10,361,542	17,995,440
Short-term debt	[1]	662,807	2,329,145
Accrued interest payable		37,024	60,655
Accrued expenses and other liabilities	[1]	166,013	206,893
Asset-backed securities issued	[1]	6,856,086	10,515,475
Total liabilities	[1]	$ 9,424,966	$ 16,168,209
Number of VIEs | investment		48	49
Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value	[1]	$ 3,402,405	$ 3,175,178
Legacy Sequoia
Variable Interest Entity [Line Items]
Number of VIEs | investment		20	20
Sequoia Choice
Variable Interest Entity [Line Items]
Number of VIEs | investment		10	9
Freddie Mac SLST
Variable Interest Entity [Line Items]
Number of VIEs | investment		2	2
Freddie Mac K-Series
Variable Interest Entity [Line Items]
Number of VIEs | investment		1	5
CAFL
Variable Interest Entity [Line Items]
Number of VIEs | investment		12	10
Servicing Investment
Variable Interest Entity [Line Items]
Number of VIEs | investment		3	3
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Other investments		$ 290,805	$ 184,802
Cash and cash equivalents		2,773	9,015
Restricted cash		30,570	21,936
Accrued interest receivable		34,546	45,772
Other assets		7,680	2,700
Total Assets		7,984,618	11,931,869
Short-term debt		244,437	152,554
Accrued interest payable		21,627	34,060
Accrued expenses and other liabilities		18,071	14,983
Asset-backed securities issued		6,856,086	10,515,475
Total liabilities		7,140,221	10,717,072
Variable Interest Entity, Primary Beneficiary | Residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		4,514,131	5,066,568
Variable Interest Entity, Primary Beneficiary | Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		2,615,038	2,192,552
Variable Interest Entity, Primary Beneficiary | Multifamily loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		489,075	4,408,524
Variable Interest Entity, Primary Beneficiary | Legacy Sequoia
Variable Interest Entity [Line Items]
Other investments		0	0
Cash and cash equivalents		0	0
Restricted cash		145	143
Accrued interest receivable		529	655
Other assets		916	460
Total Assets		306,222	409,148
Short-term debt		0	0
Accrued interest payable		230	395
Accrued expenses and other liabilities		0	0
Asset-backed securities issued		300,357	402,465
Total liabilities		300,587	402,860
Variable Interest Entity, Primary Beneficiary | Legacy Sequoia | Residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		304,632	407,890
Variable Interest Entity, Primary Beneficiary | Legacy Sequoia | Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Legacy Sequoia | Multifamily loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Sequoia Choice
Variable Interest Entity [Line Items]
Other investments		0	0
Cash and cash equivalents		0	0
Restricted cash		9	27
Accrued interest receivable		8,236	9,824
Other assets		0	0
Total Assets		2,072,633	2,301,314
Short-term debt		0	0
Accrued interest payable		6,474	7,732
Accrued expenses and other liabilities		9	27
Asset-backed securities issued		1,861,777	2,037,198
Total liabilities		1,868,260	2,044,957
Variable Interest Entity, Primary Beneficiary | Sequoia Choice | Residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		2,064,388	2,291,463
Variable Interest Entity, Primary Beneficiary | Sequoia Choice | Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Sequoia Choice | Multifamily loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Freddie Mac SLST
Variable Interest Entity [Line Items]
Other investments		0	0
Cash and cash equivalents		0	0
Restricted cash		0	0
Accrued interest receivable		6,627	7,313
Other assets		940	445
Total Assets		2,152,678	2,374,973
Short-term debt		0	0
Accrued interest payable		5,149	5,374
Accrued expenses and other liabilities		0	0
Asset-backed securities issued		1,812,008	1,918,322
Total liabilities		1,817,157	1,923,696
Variable Interest Entity, Primary Beneficiary | Freddie Mac SLST | Residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		2,145,111	2,367,215
Variable Interest Entity, Primary Beneficiary | Freddie Mac SLST | Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Freddie Mac SLST | Multifamily loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Freddie Mac K-Series
Variable Interest Entity [Line Items]
Other investments		0	0
Cash and cash equivalents		0	0
Restricted cash		0	0
Accrued interest receivable		1,342	13,539
Other assets		0	0
Total Assets		490,417	4,422,063
Short-term debt		0	0
Accrued interest payable		1,182	12,887
Accrued expenses and other liabilities		0	0
Asset-backed securities issued		464,691	4,156,239
Total liabilities		465,873	4,169,126
Variable Interest Entity, Primary Beneficiary | Freddie Mac K-Series | Residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Freddie Mac K-Series | Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Freddie Mac K-Series | Multifamily loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		489,075	4,408,524
Variable Interest Entity, Primary Beneficiary | CAFL
Variable Interest Entity [Line Items]
Other investments		0	0
Cash and cash equivalents		0	0
Restricted cash		0	0
Accrued interest receivable		11,087	9,572
Other assets		5,824	1,795
Total Assets		2,631,949	2,203,919
Short-term debt		0	0
Accrued interest payable		8,458	7,485
Accrued expenses and other liabilities		0	0
Asset-backed securities issued		2,417,253	2,001,251
Total liabilities		2,425,711	2,008,736
Variable Interest Entity, Primary Beneficiary | CAFL | Residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | CAFL | Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		2,615,038	2,192,552
Variable Interest Entity, Primary Beneficiary | CAFL | Multifamily loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Servicing Investment
Variable Interest Entity [Line Items]
Other investments		290,805	184,802
Cash and cash equivalents		2,773	9,015
Restricted cash		30,416	21,766
Accrued interest receivable		6,725	4,869
Other assets		0	0
Total Assets		330,719	220,452
Short-term debt		244,437	152,554
Accrued interest payable		134	187
Accrued expenses and other liabilities		18,062	14,956
Asset-backed securities issued		0	0
Total liabilities		262,633	167,697
Variable Interest Entity, Primary Beneficiary | Servicing Investment | Residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Servicing Investment | Business purpose residential loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		0	0
Variable Interest Entity, Primary Beneficiary | Servicing Investment | Multifamily loans, held-for-investment
Variable Interest Entity [Line Items]
Loans, at fair value		$ 0	$ 0

[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 June 30, 2020 and December 31, 2019, assets of consolidated VIEs totaled $7,984,618 and $11,931,869, respectively. At June 30, 2020 and December 31, 2019, liabilities of consolidated VIEs totaled $7,140,221 and $10,717,072, respectively. See Note 4 for further discussion.