Mortgage-Backed Securities - Summary of Present Amortized Cost, Fair Value and Unrealized Gain/Losses of Company's MBS Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	$ 6,231,729		$ 5,488,456
Total Premium	203,879		204,373
Total Discount	(828,826)		(868,887)
Amortized Cost	2,054,694		1,078,739
Allowance for credit losses	(23,949)	$ (23,591)	(18,560)	$ (16,230)	$ (13,013)	$ (7,188)
Fair Value	2,140,754		1,146,290
Gross Unrealized Gains	225,139		225,639
Gross Unrealized Losses	(115,130)		(139,528)
Net Unrealized Gain/(Loss)	110,009		86,111
Non-Agency RMBS - Senior
Debt Securities, Available-for-sale [Line Items]
Total Premium	18,895		14,641
Total Discount	(556,667)		(582,640)
Amortized Cost	485,808		505,633
Allowance for credit losses	(20,969)		(15,052)
Fair Value	644,520		676,128
Gross Unrealized Gains	184,226		192,528
Gross Unrealized Losses	(4,545)		(6,981)
Net Unrealized Gain/(Loss)	179,681		185,547
Non-Agency RMBS - Senior | Residential Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	1,023,580		1,073,632
Gross Unrealized Gains	184,226		192,528
Gross Unrealized Losses	(4,545)		(6,981)
Non-Agency RMBS - Subordinated
Debt Securities, Available-for-sale [Line Items]
Total Premium	3,325		3,609
Total Discount	(272,085)		(286,247)
Amortized Cost	389,434		300,411
Allowance for credit losses	(2,980)		(3,508)
Fair Value	385,197		276,903
Gross Unrealized Gains	21,697		16,548
Gross Unrealized Losses	(22,954)		(36,548)
Net Unrealized Gain/(Loss)	(1,257)		(20,000)
Non-Agency RMBS - Subordinated | Residential Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	658,194		583,049
Gross Unrealized Gains	21,697		16,548
Gross Unrealized Losses	(22,954)		(36,548)
Non-Agency RMBS - Interest-only
Debt Securities, Available-for-sale [Line Items]
Total Premium	154,647		157,871
Total Discount	0		0
Amortized Cost	154,647		157,871
Allowance for credit losses	0		0
Fair Value	92,119		90,775
Gross Unrealized Gains	14,914		14,394
Gross Unrealized Losses	(77,442)		(81,490)
Net Unrealized Gain/(Loss)	(62,528)		(67,096)
Non-Agency RMBS - Interest-only | Residential Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	2,699,126		2,874,680
Gross Unrealized Gains	14,914		14,394
Gross Unrealized Losses	(77,442)		(81,490)
Agency RMBS - CMO
Debt Securities, Available-for-sale [Line Items]
Total Premium	208
Total Discount	(74)
Amortized Cost	957,111
Allowance for credit losses	0
Fair Value	959,142
Gross Unrealized Gains	2,031
Gross Unrealized Losses	0
Net Unrealized Gain/(Loss)	2,031
Agency RMBS - CMO | Residential Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	956,977
Gross Unrealized Gains	2,031
Gross Unrealized Losses	0
Agency RMBS - Interest-only
Debt Securities, Available-for-sale [Line Items]
Total Premium	19,702		19,238
Total Discount	0		0
Amortized Cost	19,702		19,238
Allowance for credit losses	0		0
Fair Value	16,810		15,023
Gross Unrealized Gains	1,263		862
Gross Unrealized Losses	(4,155)		(5,077)
Net Unrealized Gain/(Loss)	(2,892)		(4,215)
Agency RMBS - Interest-only | Residential Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	384,826		392,284
Gross Unrealized Gains	1,263		862
Gross Unrealized Losses	(4,155)		(5,077)
Agency CMBS - Project loans
Debt Securities, Available-for-sale [Line Items]
Total Premium	620		1,248
Total Discount	0		0
Amortized Cost	41,510		87,820
Allowance for credit losses	0		0
Fair Value	36,302		79,179
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(5,208)		(8,641)
Net Unrealized Gain/(Loss)	(5,208)		(8,641)
Agency CMBS - Project loans | Commercial Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	40,890		86,572
Gross Unrealized Gains	0		0
Gross Unrealized Losses	(5,208)		(8,641)
Agency CMBS - Interest-only
Debt Securities, Available-for-sale [Line Items]
Total Premium	6,482		7,766
Total Discount	0		0
Amortized Cost	6,482		7,766
Allowance for credit losses	0		0
Fair Value	6,664		8,282
Gross Unrealized Gains	1,008		1,307
Gross Unrealized Losses	(826)		(791)
Net Unrealized Gain/(Loss)	182		516
Agency CMBS - Interest-only | Commercial Mortgage Backed Securities
Debt Securities, Available-for-sale [Line Items]
Principal or Notional Value	468,136		478,239
Gross Unrealized Gains	1,008		1,307
Gross Unrealized Losses	$ (826)		$ (791)