Equity - Changes to Accumulated Other Comprehensive Income (Loss) by Component (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	[1]			$ 140,688
Total other comprehensive income		$ 5,054	$ 6,905	6	$ 18,791
Balance at End of Period	[1]	140,694		140,694
Net unrealized gains on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period		190,100	185,275	186,737	164,654
Other comprehensive income (loss) before reclassifications		(5,080)	12,721	(28)	33,229
Amounts reclassified from other accumulated comprehensive income		(5,361)	(454)	(7,050)	(341)
Total other comprehensive income		(10,441)	12,267	(7,078)	32,888
Balance at End of Period		179,659	197,542	179,659	197,542
Net unrealized losses on interest rate agreements accounted for as cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period		(54,460)	(24,623)	(46,049)	(15,888)
Other comprehensive income (loss) before reclassifications		15,469	(5,401)	7,026	(14,196)
Amounts reclassified from other accumulated comprehensive income		26	39	58	99
Total other comprehensive income		15,495	(5,362)	7,084	(14,097)
Balance at End of Period		$ (38,965)	$ (29,985)	$ (38,965)	$ (29,985)

[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 June 30, 2015 and December 31, 2014, assets of consolidated VIEs totaled $1,622,636 and $1,900,208, respectively, and liabilities of consolidated VIEs totaled $1,263,249 and $1,546,490, respectively. See Note 4 for further discussion.