Residential Loans - Quarterly Activity of Residential Loans Held-for-Sale (Details) - Residential Loans $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) securitization	Mar. 31, 2021 USD ($)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal balance of loans acquired	$ 2,115,191	$ 3,096,048
Principal balance of loans sold	1,827,364	2,275,832
Principal balance of loans transferred to HFI	687,192	0
Net market valuation gains (losses) recorded	(31,451)	$ 23,429
Legacy Sequoia
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Principal balance of loans acquired	$ 102,000
Number of seasoned securities | securitization	3