Residential Loans - Activity of Residential Loans Held-for-Investment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Transfers from loans held-for-sale to loans held-for-investment	$ 1,868,656	$ 1,801,560	$ 2,062,809
Residential loans, held-for-investment \| Sequoia Choice
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Valuation adjustments	(30,356)	(15,232)
Residential loans, held-for-investment \| Freddie Mac SLST
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Valuation adjustments	35,131	63,583
Residential loans, held-for-investment \| Legacy Sequoia
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Valuation adjustments	(30,900)	5,170
Residential loans, held-for-investment \| Sequoia Choice
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Transfers from loans held-for-sale to loans held-for-investment	270,506	1,076,671
Residential loans, held-for-investment \| Redwood
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal balance of loans acquired	0	39,194
Principal balance of loans sold	0	0
Transfers from loans held-for-sale to loans held-for-investment	13,258	68,703
Transfers from loans held-for-investment to loans held-for-sale	1,870,986	22,814
Gain (loss) on assets measured at fair value on a non-recurring basis	$ (93,314)	$ 58,891

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Principal Balance of Loans Sold During Period

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For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

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-Publisher FASB
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Amount of financing receivable reclassified to held-for-sale.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Amount of increase (decrease) in investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

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-Publisher FASB
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Value of loans held-for-sale transferred to loans held in the entity's portfolio in noncash transactions.

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