Mortgage Banking Activities, Net - Components of Mortgage Banking Activities (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Other income, net	$ 2,388	$ (114)	$ 8,357	$ 3,979
Mortgage banking activities, net	63,163	59,395	200,189	24,511
Residential Mortgage Banking Activities, Net
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Other income, net	1,089	(715)	3,305	(7,069)
Mortgage banking activities, net	32,946	11,864	115,646	(19,222)
Residential Mortgage Banking Activities, Net \| Residential loans, at fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	27,862	12,589	75,496	19,151
Residential Mortgage Banking Activities, Net \| Trading securities
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	32	0	(342)	0
Residential Mortgage Banking Activities, Net \| Risk management derivatives
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Risk management derivatives	3,963	(10)	37,187	(31,304)
Business Purpose Mortgage Banking Activities, Net:
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	3,433	938	6,702	(4,256)
Other income, net	8,747	3,491	22,236	13,407
Mortgage banking activities, net	30,217	47,531	84,543	43,733
Business Purpose Mortgage Banking Activities, Net: \| Risk management derivatives
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Risk management derivatives	(424)	(89)	930	(21,627)
Business Purpose Mortgage Banking Activities, Net: \| Single-family rental loans, at fair value
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	$ 18,461	$ 43,191	$ 54,675	$ 56,209

Increase (Decrease) in Fair Value Adjustments on Assets

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- Definition

The net income attributable to mortgage banking activities. This includes market valuations related to residential and commercial loans, Sequoia IOs, and mortgage banking derivatives, as well as realized gains or losses associated with mortgage loan sales.

+ References

No definition available.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of unrealized gain (loss) related to the fair value of price risk derivatives designated as fair value hedging instruments, as offset by the gain (loss) on the hedged item to the extent that the fair value hedge is determined to be effective.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959

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- Definition

Amount of revenue and income classified as other.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.4)
-URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

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