Fair Value of Financial Instruments - Carrying Values and Estimated Fair Values of Assets and Liabilities (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019
Assets
Trading securities		$ 142,699	$ 860,540
Available-for-sale securities		173,737	239,334
MSRs		249,705	151,582
Derivative assets	[1]	357	35,701
Pledged collateral		33,105	32,945
Liabilities
Contingent consideration		14,953	28,484
Derivative liabilities	[1]	1,932	163,424
Residential Loans
Assets
MSRs		266,948	169,204
Carrying Value
Assets
Trading securities		142,699	860,540
Available-for-sale securities		173,737	239,334
Cash and cash equivalents		528,612	196,966
Shared home appreciation options			45,085
Restricted cash		44,496	93,867
Accrued interest receivable		44,134	71,058
Derivative assets		357	35,701
Margin receivable		2,746	209,776
FHLBC stock		5,000	43,393
Guarantee asset		770	1,686
Pledged collateral		33,105	32,945
Liabilities
Accrued interest payable		37,024	60,655
Margin payable		0	1,700
Guarantee obligation		12,350	14,009
Contingent consideration		14,953	28,484
Derivative liabilities		1,932	163,424
ABS issued at fair value		6,856,086	10,515,475
FHLBC long-term borrowings		1,000	1,999,999
Other long-term debt, net		1,088,609	183,520
Convertible notes, net		509,868	631,125
Trust preferred securities and subordinated notes, net		138,651	138,628
Carrying Value | Servicer advance investments
Assets
MSRs		266,948	169,204
Carrying Value | MSRs
Assets
MSRs		19,661	42,224
Carrying Value | Excess MSRs
Assets
REO		36,197	31,814
Carrying Value | REO
Assets
REO		9,780	9,462
Carrying Value | Short-term debt facilities
Liabilities
Short-term debt facilities		418,370	2,176,591
Carrying Value | Short-term debt - servicer advance financing
Liabilities
Short-term debt facilities		244,437	152,554
Carrying Value | Residential Loans | Residential loans, at fair value
Assets
Loans, held-for-sale		20,098	536,385
Carrying Value | Residential Loans | Residential loans, held-for-investment
Assets
Loans receivable, fair value		4,514,131	7,178,465
Carrying Value | Residential Loans | Business purpose residential loans, held-for-sale
Assets
Loans, held-for-sale		379,795	331,565
Carrying Value | Residential Loans | Business purpose residential loans, held-for-investment
Assets
Loans receivable, fair value		3,402,405	3,175,178
Carrying Value | Residential Loans | Multifamily loans
Assets
Loans receivable, fair value		489,075	4,408,524
Fair Value
Assets
Trading securities		142,699	860,540
Available-for-sale securities		173,737	239,334
Cash and cash equivalents		528,612	196,966
Shared home appreciation options		40,851	45,085
Restricted cash		44,496	93,867
Accrued interest receivable		44,134	71,058
Derivative assets		357	35,701
Margin receivable		2,746	209,776
FHLBC stock		5,000	43,393
Guarantee asset		770	1,686
Pledged collateral		33,105	32,945
Liabilities
Accrued interest payable		37,024	60,655
Margin payable		0	1,700
Guarantee obligation		10,995	13,754
Contingent consideration		14,953	28,484
Derivative liabilities		1,932	163,424
ABS issued at fair value		6,856,086	10,515,475
FHLBC long-term borrowings		1,000	1,999,999
Other long-term debt, net		1,082,327	184,666
Convertible notes, net		469,360	661,985
Trust preferred securities and subordinated notes, net		55,800	99,045
Fair Value | Servicer advance investments
Assets
MSRs		266,948	169,204
Fair Value | MSRs
Assets
MSRs		19,661	42,224
Fair Value | Excess MSRs
Assets
REO		36,197	31,814
Fair Value | REO
Assets
REO		10,014	10,389
Fair Value | Short-term debt facilities
Liabilities
Short-term debt facilities		418,370	2,176,591
Fair Value | Short-term debt - servicer advance financing
Liabilities
Short-term debt facilities		244,437	152,554
Fair Value | Residential Loans | Residential loans, at fair value
Assets
Loans, held-for-sale		20,098	536,509
Fair Value | Residential Loans | Residential loans, held-for-investment
Assets
Loans receivable, fair value		4,514,131	7,178,465
Fair Value | Residential Loans | Business purpose residential loans, held-for-sale
Assets
Loans, held-for-sale		379,795	331,565
Fair Value | Residential Loans | Business purpose residential loans, held-for-investment
Assets
Loans receivable, fair value		3,402,405	3,175,178
Fair Value | Residential Loans | Multifamily loans
Assets
Loans receivable, fair value		489,075	4,408,524
Shared home appreciation options
Assets
Shared home appreciation options		$ 40,851	$ 45,085

[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.