Components of Corporate/Other (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Interest income	$ 57,492		$ 57,420	$ 57,719	$ 53,525	$ 53,397		$ 59,723	$ 59,523	$ 58,740	$ 226,156		$ 231,384		$ 217,179
Interest expense	(19,528)		(21,725)	(21,416)	(18,302)	(32,971)		(28,285)	(28,881)	(30,655)	(80,971)		(120,705)		(98,978)
Net interest income (loss)	37,964		35,695	36,303	35,223	20,426		31,438	30,642	28,085	145,185		110,679		118,201
Provision for loan losses											(4,737)		(3,648)		(16,151)
Mortgage banking activities, net											100,676		36,319
MSR income, net											20,309		(1,391)
Other market valuation adjustments, net											(5,709)		1,539
Realized gains, net											25,259		54,921		10,946
Direct operating expenses											(84,789)		(65,359)		(47,741)
Other expense											(12,000)
Provision for income taxes											(10,948)		(1,291)		(42)
Net Income Attributable to Redwood Trust, Inc.	25,134		21,929	65,573	60,160	42,078		39,701	19,527	30,463	173,246		131,769		26,343
Supplemental Disclosures
Residential loans	2,166,434					2,835,470					2,166,434		2,835,470
Total assets	4,608,528	[1]				4,444,098	[1]				4,608,528	[1]	4,444,098	[1]
Non-cash amortization expense											26,442		24,660
Residential Loans Held for Investment
Supplemental Disclosures
Residential loans	1,762,167					2,272,812					1,762,167		2,272,812
Legacy Consolidated VIEs
Segment Reporting Information [Line Items]
Interest income											33,663		92,296
Interest expense											(25,876)		(95,807)
Net interest income (loss)											7,787		(3,511)
Provision for loan losses											(1,449)		(171)
Mortgage banking activities, net
MSR income, net
Other market valuation adjustments, net											(613)		6,144
Realized gains, net											284		22,470
Direct operating expenses											(231)		(148)
Net Income Attributable to Redwood Trust, Inc.											5,778		24,784
Supplemental Disclosures
Total assets	1,770,089					2,284,567					1,770,089		2,284,567
Non-cash amortization expense											(5,769)		(3,426)
Legacy Consolidated VIEs | Residential Loans Held for Investment
Supplemental Disclosures
Residential loans	1,762,167					2,272,812					1,762,167		2,272,812
Other
Segment Reporting Information [Line Items]
Interest income											157		60
Interest expense											(22,184)		(9,531)
Net interest income (loss)											(22,027)		(9,471)
Mortgage banking activities, net
MSR income, net
Direct operating expenses											(49,882)		(35,475)
Other expense											(12,000)
Provision for income taxes											1,853		(1,278)
Net Income Attributable to Redwood Trust, Inc.											(82,056)		(46,224)
Supplemental Disclosures
Total assets	212,999					142,796					212,999		142,796
Non-cash amortization expense											(1,569)		(46)
Corporate/Other
Segment Reporting Information [Line Items]
Interest income											33,820		92,356
Interest expense											(48,060)		(105,338)
Net interest income (loss)											(14,240)		(12,982)
Provision for loan losses											(1,449)		(171)
Mortgage banking activities, net
MSR income, net
Other market valuation adjustments, net											(613)		6,144
Realized gains, net											284		22,470
Direct operating expenses											(50,113)		(35,623)
Other expense											(12,000)
Provision for income taxes											1,853		(1,278)
Net Income Attributable to Redwood Trust, Inc.											(76,278)		(21,440)
Supplemental Disclosures
Residential loans	1,762,167					2,272,812					1,762,167		2,272,812
Total assets	1,983,088					2,427,363					1,983,088		2,427,363
Non-cash amortization expense											(7,338)		(3,472)
Corporate/Other | Residential Loans Held for Investment
Supplemental Disclosures
Residential loans	$ 1,762,167					$ 2,272,812					$ 1,762,167		$ 2,272,812

[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 the primary beneficiary (Redwood Trust, Inc.). At December 31, 2013 and 2012, assets of consolidated VIEs totaled $2,299,576 and $2,893,117, respectively, and liabilities of consolidated VIEs totaled $1,944,911 and $2,532,916 respectively. See Note 4 for further discussion.