Investment in Securities (Summary of Investment in Securities) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2024	Dec. 31, 2023
Securities, Available-for-sale [Line Items]
Current Principal		$ 1,412,313	$ 1,640,771
Unamortized Premium (Discount)		(309,889)	(310,544)
Debt Securities, Available-for-Sale, Amortized Cost		1,234,745	1,445,337
Gross Unrealized Gains		34,955	35,790
Gross Unrealized Losses		(105,970)	(117,053)
Investment Owned At Fair Value, Net		1,163,730	1,364,074
Securities, at fair value(1)(2)	[1],[2]	1,328,848	1,518,377
Securities sold short, at fair value		$ (165,118)	$ (154,303)
Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.71%	4.78%
Weighted Average Yield		5.72%	5.71%
Weighted average life		5 years 6 months 18 days	5 years 5 months 1 day
Long
Securities, Available-for-sale [Line Items]
Current Principal		$ 1,581,016	$ 1,798,051
Unamortized Premium (Discount)		(309,386)	(310,520)
Debt Securities, Available-for-Sale, Amortized Cost		1,403,951	1,602,641
Gross Unrealized Gains		30,623	32,170
Gross Unrealized Losses		(105,726)	(116,434)
Securities, at fair value(1)(2)		$ 1,328,848	$ 1,518,377
Long | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.89%	4.95%
Weighted Average Yield		6.05%	5.99%
Weighted average life		6 years 3 days	5 years 9 months 18 days
Long | 15-year fixed-rate mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 56,106	$ 57,987
Unamortized Premium (Discount)		220	252
Debt Securities, Available-for-Sale, Amortized Cost		56,326	58,239
Gross Unrealized Gains		5	22
Gross Unrealized Losses		(4,562)	(4,225)
Securities, at fair value(1)(2)		$ 51,769	$ 54,036
Long | 15-year fixed-rate mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		2.57%	2.58%
Weighted Average Yield		2.41%	2.42%
Weighted average life		3 years 5 months 1 day	3 years 5 months 23 days
Long | 20-year fixed-rate mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 2,324	$ 2,368
Unamortized Premium (Discount)		107	114
Debt Securities, Available-for-Sale, Amortized Cost		2,431	2,482
Gross Unrealized Gains		0	0
Gross Unrealized Losses		(428)	(404)
Securities, at fair value(1)(2)		$ 2,003	$ 2,078
Long | 20-year fixed-rate mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		2.29%	2.29%
Weighted Average Yield		1.45%	1.48%
Weighted average life		6 years 2 months 8 days	6 years 3 months
Long | 30-year fixed-rate mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 599,815	$ 783,123
Unamortized Premium (Discount)		(9,708)	(6,744)
Debt Securities, Available-for-Sale, Amortized Cost		590,107	776,379
Gross Unrealized Gains		1,453	4,313
Gross Unrealized Losses		(35,526)	(38,595)
Securities, at fair value(1)(2)		$ 556,034	$ 742,097
Long | 30-year fixed-rate mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.02%	4.04%
Weighted Average Yield		4.09%	4.04%
Weighted average life		6 years 9 months 7 days	6 years 7 months 9 days
Long | Adjustable rate mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 5,171	$ 5,252
Unamortized Premium (Discount)		532	568
Debt Securities, Available-for-Sale, Amortized Cost		5,703	5,820
Gross Unrealized Gains		0	0
Gross Unrealized Losses		(660)	(690)
Securities, at fair value(1)(2)		$ 5,043	$ 5,130
Long | Adjustable rate mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		3.88%	3.81%
Weighted Average Yield		2.10%	2.09%
Weighted average life		4 years 9 months 25 days	4 years 5 months 1 day
Long | Reverse mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 35,416	$ 36,196
Unamortized Premium (Discount)		3,211	3,928
Debt Securities, Available-for-Sale, Amortized Cost		38,627	40,124
Gross Unrealized Gains		233	34
Gross Unrealized Losses		(1,948)	(2,987)
Securities, at fair value(1)(2)		$ 36,912	$ 37,171
Long | Reverse mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		5.98%	5.37%
Weighted Average Yield		3.38%	3.55%
Weighted average life		4 years 9 months 18 days	4 years 9 months 3 days
Long | Interest only securities
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 10,291	$ 11,891
Gross Unrealized Gains		1,090	1,320
Gross Unrealized Losses		(570)	(499)
Securities, at fair value(1)(2)		$ 10,811	$ 12,712
Long | Interest only securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		1.23%	1.08%
Weighted Average Yield		11.69%	13.18%
Weighted average life		5 years 9 months	5 years 4 months 9 days
Long | Non-Agency RMBS
Securities, Available-for-sale [Line Items]
Current Principal		$ 336,052	$ 427,431
Unamortized Premium (Discount)		(122,112)	(139,654)
Debt Securities, Available-for-Sale, Amortized Cost		213,940	287,777
Gross Unrealized Gains		12,616	11,369
Gross Unrealized Losses		(22,760)	(29,672)
Securities, at fair value(1)(2)		$ 203,796	$ 269,474
Long | Non-Agency RMBS | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		5.18%	5.07%
Weighted Average Yield		8.77%	8.96%
Weighted average life		4 years 11 months 1 day	4 years 8 months 23 days
Long | CMBS
Securities, Available-for-sale [Line Items]
Current Principal		$ 51,171	$ 74,591
Unamortized Premium (Discount)		(20,689)	(20,389)
Debt Securities, Available-for-Sale, Amortized Cost		30,482	54,202
Gross Unrealized Gains		667	349
Gross Unrealized Losses		(11,348)	(11,780)
Securities, at fair value(1)(2)		$ 19,801	$ 42,771
Long | CMBS | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		3.22%	4.87%
Weighted Average Yield		9.09%	8.93%
Weighted average life		6 years 8 months 12 days	4 years 8 months 19 days
Long | Non-Agency IOs
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 32,038	$ 35,214
Gross Unrealized Gains		6,560	6,212
Gross Unrealized Losses		(2,074)	(2,650)
Securities, at fair value(1)(2)		$ 36,524	$ 38,776
Long | Non-Agency IOs | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		0.17%	0.17%
Weighted Average Yield		13.57%	14.57%
Weighted average life		7 years 10 months 6 days	7 years 5 months 15 days
Long | CLOs
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 67,872	$ 44,939
Gross Unrealized Gains		2,477	1,873
Gross Unrealized Losses		(5,649)	(8,834)
Securities, at fair value(1)(2)		$ 64,700	$ 37,978
Long | CLOs | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		2.86%	2.27%
Weighted Average Yield		11.40%	11.81%
Weighted average life		4 years 8 months 8 days	4 years 5 months 15 days
Long | Other asset-backed securities
Securities, Available-for-sale [Line Items]
Current Principal		$ 58,732	$ 16,416
Unamortized Premium (Discount)		(43,923)	(8,956)
Debt Securities, Available-for-Sale, Amortized Cost		14,809	7,460
Gross Unrealized Gains		141	256
Gross Unrealized Losses		(261)	(20)
Securities, at fair value(1)(2)		$ 14,689	$ 7,696
Long | Other asset-backed securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.50%	7.16%
Weighted Average Yield		24.22%	13.85%
Weighted average life		3 years 4 months 9 days	2 years 5 months 26 days
Long | Asset-backed securities, backed by consumer loans
Securities, Available-for-sale [Line Items]
Current Principal		$ 151,568	$ 151,310
Unamortized Premium (Discount)		(70,659)	(67,159)
Debt Securities, Available-for-Sale, Amortized Cost		80,909	84,151
Gross Unrealized Gains		1,560	1,577
Gross Unrealized Losses		(10,925)	(11,502)
Securities, at fair value(1)(2)		$ 71,544	$ 74,226
Long | Asset-backed securities, backed by consumer loans | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		12.00%	12.00%
Weighted Average Yield		10.52%	11.38%
Weighted average life		1 year 6 months 18 days	1 year 6 months
Long | Corporate debt securities
Securities, Available-for-sale [Line Items]
Current Principal		$ 61,323	$ 30,944
Unamortized Premium (Discount)		(49,312)	(23,191)
Debt Securities, Available-for-Sale, Amortized Cost		12,011	7,753
Gross Unrealized Gains		1,752	579
Gross Unrealized Losses		(834)	(291)
Securities, at fair value(1)(2)		$ 12,929	$ 8,041
Long | Corporate debt securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		0.00%	0.00%
Weighted Average Yield		0.00%	0.00%
Weighted average life		2 years 2 months 4 days	1 year 11 months 4 days
Long | Corporate equity securities
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 22,120	$ 23,066
Gross Unrealized Gains		1,547	1,851
Gross Unrealized Losses		(6,412)	(3,789)
Securities, at fair value(1)(2)		17,255	21,128
Long | U.S. Treasury securities
Securities, Available-for-sale [Line Items]
Current Principal		223,338	212,433
Unamortized Premium (Discount)		2,947	(49,289)
Debt Securities, Available-for-Sale, Amortized Cost		226,285	163,144
Gross Unrealized Gains		522	2,415
Gross Unrealized Losses		(1,769)	(496)
Securities, at fair value(1)(2)		$ 225,038	$ 165,063
Long | U.S. Treasury securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.29%	4.25%
Weighted Average Yield		4.04%	4.01%
Weighted average life		7 years 9 months 14 days	7 years 5 months 4 days
Short
Securities, Available-for-sale [Line Items]
Current Principal		$ (168,703)	$ (157,280)
Unamortized Premium (Discount)		(503)	(24)
Investment Sold, Not yet Purchased, Sale Proceeds		(169,206)	(157,304)
Gross Unrealized Gains		4,332	3,620
Gross Unrealized Losses		(244)	(619)
Securities sold short, at fair value		$ (165,118)	$ (154,303)
Short | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		2.96%	2.87%
Weighted Average Yield		3.09%	3.00%
Weighted average life		1 year 10 months 6 days	1 year 9 months 7 days
Short | U.S. Treasury securities
Securities, Available-for-sale [Line Items]
Current Principal		$ (142,128)	$ (130,121)
Unamortized Premium (Discount)		645	533
Investment Sold, Not yet Purchased, Sale Proceeds		(141,483)	(129,588)
Gross Unrealized Gains		2,333	2,094
Gross Unrealized Losses		(244)	(619)
Securities sold short, at fair value		$ (139,394)	$ (128,113)
Short | U.S. Treasury securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		3.52%	3.47%
Weighted Average Yield		3.66%	3.61%
Weighted average life		2 years 3 days	1 year 10 months 17 days
Short | European sovereign bonds
Securities, Available-for-sale [Line Items]
Current Principal		$ (26,575)	$ (27,159)
Unamortized Premium (Discount)		(1,148)	(557)
Investment Sold, Not yet Purchased, Sale Proceeds		(27,723)	(27,716)
Gross Unrealized Gains		1,999	1,526
Gross Unrealized Losses		0	0
Securities sold short, at fair value		$ (25,724)	$ (26,190)
Short | European sovereign bonds | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		0.01%	0.01%
Weighted Average Yield		0.15%	0.15%
Weighted average life		11 months 8 days	1 year 2 months 12 days

[1] Ellington Financial Inc.'s Consolidated Balance Sheets include assets and liabilities of variable interest entities it has consolidated. See Note 12 for additional details on Ellington Financial Inc.'s consolidated variable interest entities.

[2] Includes assets pledged as collateral to counterparties. See Note 14 for additional details on the Company's borrowings and related collateral.