Segment Information - Financial Information by Segment (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Interest income		$ 56,334	$ 60,906	$ 66,787	$ 62,328	$ 68,829	$ 63,484	$ 63,373	$ 63,746	$ 246,355	$ 259,432	$ 242,070
Interest expense		(20,537)	(21,597)	(22,444)	(23,950)	(25,039)	(23,875)	(23,008)	(23,961)	(88,528)	(95,883)	(87,463)
Net Interest Income		35,797	39,309	44,343	38,378	43,790	39,609	40,365	39,785	157,827	163,549	154,607
Reversal of provision for loan losses		0	859	6,532	(289)					7,102	355	(961)
Non-interest income
Mortgage banking activities, net										38,691	10,972	34,994
MSR income (loss), net										14,353	(3,922)	(4,261)
Investment fair value changes, net										(28,574)	(21,357)	(10,202)
Other income										6,338	3,192	1,781
Realized gains, net										28,009	36,369	15,478
Total non-interest income, net		9,763	33,712	10,888	4,454	19,593	(3,412)	14,104	(5,031)	58,817	25,254	37,790
Direct operating expenses		(17,824)	(20,355)	(20,155)	(30,452)	(22,638)	(24,497)	(25,218)	(25,063)	(88,786)	(97,416)	(90,123)
(Provision for) benefit from income taxes										(3,708)	10,346	(744)
Net Income		25,355	$ 52,553	$ 41,281	$ 12,063	41,059	$ 19,164	$ 27,064	$ 14,801	131,252	102,088	100,569
Supplemental Disclosures
Non-cash amortization income (expense)										25,704	32,403	33,698
Hedging allocations											0
Real estate securities	[1]	1,018,439				1,233,256				1,018,439	1,233,256
MSR Fair Value	[1]	118,526				191,976				118,526	191,976
Total assets	[1]	5,483,477				6,220,047				5,483,477	6,220,047
Residential Loans
Supplemental Disclosures
Loan market valuation adjustment		3,888,051				3,928,803				3,888,051	3,928,803
Commercial Loans
Supplemental Disclosures
Loan market valuation adjustment		2,700				402,647				2,700	402,647
Operating Segments | Residential Mortgage Banking
Segment Reporting Information [Line Items]
Interest income										33,661	52,260	58,272
Interest expense										(14,191)	(17,207)	(12,776)
Net Interest Income										19,470	35,053	45,496
Reversal of provision for loan losses										0	0	0
Non-interest income
Mortgage banking activities, net										40,753	8,268	21,554
MSR income (loss), net										0	0	0
Investment fair value changes, net										0	0	0
Other income										0	0	0
Realized gains, net										0	0	0
Total non-interest income, net										40,753	8,268	21,554
Direct operating expenses										(23,252)	(43,182)	(37,664)
(Provision for) benefit from income taxes										(1,860)	4,169	(1,774)
Net Income										35,111	4,308	27,612
Supplemental Disclosures
Non-cash amortization income (expense)										(130)	(186)	(181)
Hedging allocations											1,120
Real estate securities		0				197,007				0	197,007
MSR Fair Value		0				0				0	0
Total assets		866,356				1,347,492				866,356	1,347,492
Operating Segments | Residential Mortgage Banking | Residential Loans
Supplemental Disclosures
Loan market valuation adjustment		835,399				1,115,738				835,399	1,115,738
Operating Segments | Residential Mortgage Banking | Commercial Loans
Supplemental Disclosures
Loan market valuation adjustment		0				0				0	0
Operating Segments | Residential Investments
Segment Reporting Information [Line Items]
Interest income										160,174	135,395	110,433
Interest expense										(18,394)	(11,204)	(11,848)
Net Interest Income										141,780	124,191	98,585
Reversal of provision for loan losses										0	0	0
Non-interest income
Mortgage banking activities, net										0	0	0
MSR income (loss), net										14,353	(3,922)	(4,261)
Investment fair value changes, net										(26,945)	(20,089)	(9,178)
Other income										6,070	3,192	181
Realized gains, net										22,516	36,369	13,777
Total non-interest income, net										15,994	15,550	519
Direct operating expenses										(9,042)	(4,346)	(3,681)
(Provision for) benefit from income taxes										(1,848)	847	1,340
Net Income										146,884	136,242	96,763
Supplemental Disclosures
Non-cash amortization income (expense)										29,830	36,850	42,784
Hedging allocations											(1,070)
Real estate securities		926,669				1,028,171				926,669	1,028,171
MSR Fair Value		118,526				191,976				118,526	191,976
Total assets		3,518,518				3,140,604				3,518,518	3,140,604
Operating Segments | Residential Investments | Residential Loans
Supplemental Disclosures
Loan market valuation adjustment		2,261,016				1,791,195				2,261,016	1,791,195
Operating Segments | Residential Investments | Commercial Loans
Supplemental Disclosures
Loan market valuation adjustment		0				0				0	0
Operating Segments | Commercial
Segment Reporting Information [Line Items]
Interest income										32,780	46,933	47,567
Interest expense										(5,001)	(13,809)	(15,836)
Net Interest Income										27,779	33,124	31,731
Reversal of provision for loan losses										7,102	355	(84)
Non-interest income
Mortgage banking activities, net										(2,062)	2,704	13,440
MSR income (loss), net										0	0	0
Investment fair value changes, net										2,578	0	0
Other income										268	0	0
Realized gains, net										5,201	0	0
Total non-interest income, net										5,985	2,704	13,440
Direct operating expenses										(2,731)	(11,331)	(11,324)
(Provision for) benefit from income taxes										0	1,452	(234)
Net Income										38,135	26,304	33,529
Supplemental Disclosures
Non-cash amortization income (expense)										(24)	(267)	(673)
Hedging allocations											0
Real estate securities		91,770				8,078				91,770	8,078
MSR Fair Value		0				0				0	0
Total assets		97,017				415,716				97,017	415,716
Operating Segments | Commercial | Residential Loans
Supplemental Disclosures
Loan market valuation adjustment		0				0				0	0
Operating Segments | Commercial | Commercial Loans
Supplemental Disclosures
Loan market valuation adjustment		2,700				402,647				2,700	402,647
Corporate/ Other
Segment Reporting Information [Line Items]
Interest income										19,740	24,844	25,798
Interest expense										(50,942)	(53,663)	(47,003)
Net Interest Income										(31,202)	(28,819)	(21,205)
Reversal of provision for loan losses										0	0	(877)
Non-interest income
Mortgage banking activities, net										0	0	0
MSR income (loss), net										0	0	0
Investment fair value changes, net										(4,207)	(1,268)	(1,024)
Other income										0	0	1,600
Realized gains, net										292	0	1,701
Total non-interest income, net										(3,915)	(1,268)	2,277
Direct operating expenses										(53,761)	(38,557)	(37,454)
(Provision for) benefit from income taxes										0	3,878	(76)
Net Income										(88,878)	(64,766)	(57,335)
Supplemental Disclosures
Non-cash amortization income (expense)										(3,972)	(3,994)	$ (8,232)
Hedging allocations											(50)
Real estate securities		0				0				0	0
MSR Fair Value		0				0				0	0
Total assets		1,001,586				1,316,235				1,001,586	1,316,235
Corporate/ Other | Residential Loans
Supplemental Disclosures
Loan market valuation adjustment		791,636				1,021,870				791,636	1,021,870
Corporate/ Other | Commercial Loans
Supplemental Disclosures
Loan market valuation adjustment		$ 0				$ 0				$ 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 December 31, 2016 and December 31, 2015, assets of consolidated VIEs totaled $798,317 and $1,195,574, respectively. At December 31, 2016 and December 31, 2015, liabilities of consolidated VIEs totaled $773,980 and $1,050,861, respectively. See Note 4 for further discussion.