Basis of Presentation - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands		Oct. 15, 2019	Mar. 01, 2019	Dec. 31, 2019	Dec. 31, 2018
Purchase price:
Contingent consideration, at fair value				$ 28,484	$ 0
Allocated to:
Goodwill	[1]			88,675	0
5 Arches, LLC
Purchase price:
Cash			$ 12,575
Contingent consideration, at fair value			24,621	28,000
Purchase option, at fair value			5,082
Equity method investment, at fair value			8,052
Allocated to:
Business purpose residential loans, at fair value			2,022
Cash and cash equivalents			2,128
Restricted cash			9,082
Other assets			5,473
Goodwill			28,747	28,747	0
Intangible assets			24,800
Deferred tax asset			0
Total assets acquired			72,252
Asset-backed securities issued, at fair value			0
Short-term debt, net			3,800
Accrued expenses and other liabilities			13,920
Deferred tax asset			4,202
Total liabilities assumed			21,922
Total net assets acquired			50,330
CoreVest LLC
Purchase price:
Cash		$ 482,311
Contingent consideration, at fair value		0
Purchase option, at fair value		0
Equity method investment, at fair value		0
Allocated to:
Business purpose residential loans, at fair value		2,610,490
Cash and cash equivalents		30,685
Restricted cash		0
Other assets		67,420
Goodwill		59,928		$ 59,928	$ 0
Intangible assets		56,500	$ 57,000
Deferred tax asset		2,577
Total assets acquired		2,827,600
Asset-backed securities issued, at fair value		1,656,023
Short-term debt, net		663,275
Accrued expenses and other liabilities		25,991
Deferred tax asset		0
Total liabilities assumed		2,345,289
Total net assets acquired		$ 482,311

[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, 2019 and December 31, 2018, assets of consolidated VIEs totaled $11,931,869 and $6,331,191, respectively. At December 31, 2019 and December 31, 2018, liabilities of consolidated VIEs totaled $10,717,072 and $5,709,807, respectively. See Note 4 for further discussion.