Investment Securities Available For Sale, at Fair Value - Realized Gain or Loss Activity (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds	$ 432,585	$ 1,820,194	$ 97,951
Realized Gains	16,006	19,679	21,971
Realized Losses	(4,786)	(81,208)	(156)
Net Realized Gains (Losses)	11,220	(61,529)	21,815
Total Agency
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds		1,138,377
Realized Gains		11,068
Realized Losses		(16,063)
Net Realized Gains (Losses)		(4,995)
Agency RMBS
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds	123,622	992,966
Realized Gains	0	5,402
Realized Losses	(3,480)	(15,854)
Net Realized Gains (Losses)	(3,480)	(10,452)
Agency RMBS \| Agency ARMs
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds		49,892
Realized Gains		44
Realized Losses		(4,157)
Net Realized Gains (Losses)		(4,113)
Agency RMBS \| Agency Fixed Rate
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds		943,074
Realized Gains		5,358
Realized Losses		(11,697)
Net Realized Gains (Losses)		(6,339)
Agency CMBS
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds		145,411
Realized Gains		5,666
Realized Losses		(209)
Net Realized Gains (Losses)		5,457
Non-Agency RMBS
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds	176,166	433,076	1,021
Realized Gains	4,923	435	33
Realized Losses	(854)	(34,856)	0
Net Realized Gains (Losses)	4,069	(34,421)	33
Non-Agency RMBS \| Non Agency RMBS Held In Securitization Trust
Debt Securities, Available-for-sale [Line Items]
Net Realized Gains (Losses)	(5,500)
CMBS
Debt Securities, Available-for-sale [Line Items]
Sales Proceeds	132,797	248,741	96,930
Realized Gains	11,083	8,176	21,938
Realized Losses	(452)	(30,289)	(156)
Net Realized Gains (Losses)	$ 10,631	$ (22,113)	$ 21,782

Proceeds Including Receivable For Unsettled Trades From Sale Of Debt Securities, Available-For-Sale

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- Definition

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563

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- Definition

Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563

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- Definition

Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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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

No definition available.

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