Residential Loans - Summary of Classifications and Carrying Value of Residential Loans (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Dec. 31, 2018
At fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		$ 926,000	$ 1,050,000
At lower of cost or fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		100	100
Total held-for-sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans	[1]	925,887	1,048,801
Legacy Sequoia | Held-for-investment at fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		429,000	520,000
Sequoia Choice | Held-for-investment at fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		2,620,000	2,080,000
Freddie Mac SLST | Held-for-investment at fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		2,440,000	1,220,000
Redwood | Held-for-investment at fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans			2,380,000
Residential Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		8,681,803	7,254,742
Residential Loans | At fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		925,780	1,048,690
Residential Loans | At lower of cost or fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		107	111
Residential Loans | Total held-for-sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		925,887	1,048,801
Residential Loans | Held-for-investment at fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		7,755,916	6,205,941
Residential Loans | Legacy Sequoia
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		429,159	519,958
Residential Loans | Legacy Sequoia | At fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Legacy Sequoia | At lower of cost or fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Legacy Sequoia | Total held-for-sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Legacy Sequoia | Held-for-investment at fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		429,159	519,958
Residential Loans | Sequoia Choice
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		2,618,316	2,079,382
Residential Loans | Sequoia Choice | At fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Sequoia Choice | At lower of cost or fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Sequoia Choice | Total held-for-sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Sequoia Choice | Held-for-investment at fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		2,618,316	2,079,382
Residential Loans | Freddie Mac SLST
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		2,441,223	1,222,669
Residential Loans | Freddie Mac SLST | At fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Freddie Mac SLST | At lower of cost or fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Freddie Mac SLST | Total held-for-sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		0	0
Residential Loans | Freddie Mac SLST | Held-for-investment at fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		2,441,223	1,222,669
Residential Loans | Redwood
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		3,193,105	3,432,733
Residential Loans | Redwood | At fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		925,780	1,048,690
Residential Loans | Redwood | At lower of cost or fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		107	111
Residential Loans | Redwood | Total held-for-sale
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		925,887	1,048,801
Residential Loans | Redwood | Held-for-investment at fair value | Jumbo Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Residential loans		$ 2,267,218	$ 2,383,932

[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 September 30, 2019 and December 31, 2018, assets of consolidated VIEs totaled $9,596,537 and $6,331,191, respectively. At September 30, 2019 and December 31, 2018, liabilities of consolidated VIEs totaled $8,582,595 and $5,709,807, respectively. See Note 4 for further discussion.