Investment in Securities (Summary of Investment in Securities) (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2025	Dec. 31, 2024
Securities, Available-for-sale [Line Items]
Current Principal		$ 898,885	$ 903,464
Unamortized Premium (Discount)		(483,221)	(389,777)
Debt Securities, Available-for-Sale, Amortized Cost		696,264	700,268
Gross Unrealized Gains		52,767	48,787
Gross Unrealized Losses		(73,226)	(80,375)
Investment Owned At Fair Value, Net		675,805	668,680
Securities, at fair value(1)(2)	[1],[2]	909,851	962,254
Securities sold short, at fair value		$ (234,046)	$ (293,574)
Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.64%	4.77%
Weighted Average Yield		9.07%	6.58%
Weighted average life		5 years 3 months 3 days	5 years 11 months 26 days
Long
Securities, Available-for-sale [Line Items]
Current Principal		$ 1,131,814	$ 1,203,041
Unamortized Premium (Discount)		(482,623)	(387,697)
Debt Securities, Available-for-Sale, Amortized Cost		929,791	1,001,925
Gross Unrealized Gains		52,338	40,695
Gross Unrealized Losses		(72,278)	(80,366)
Securities, at fair value(1)(2)		$ 909,851	$ 962,254
Long | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.78%	4.95%
Weighted Average Yield		10.42%	7.47%
Weighted average life		4 years 9 months 14 days	5 years 10 months 17 days
Long | 15-year fixed-rate mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 5,588	$ 7,275
Unamortized Premium (Discount)		(26)	(34)
Debt Securities, Available-for-Sale, Amortized Cost		5,562	7,241
Gross Unrealized Gains		37	0
Gross Unrealized Losses		(106)	(226)
Securities, at fair value(1)(2)		$ 5,493	$ 7,015
Long | 15-year fixed-rate mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		3.50%	3.51%
Weighted Average Yield		3.79%	3.72%
Weighted average life		2 years 6 months 21 days	2 years 8 months 26 days
Long | 30-year fixed-rate mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 215,068	$ 264,915
Unamortized Premium (Discount)		(279)	239
Debt Securities, Available-for-Sale, Amortized Cost		214,789	265,154
Gross Unrealized Gains		2,024	574
Gross Unrealized Losses		(15,145)	(22,367)
Securities, at fair value(1)(2)		$ 201,668	$ 243,361
Long | 30-year fixed-rate mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		3.93%	4.08%
Weighted Average Yield		3.84%	3.94%
Weighted average life		7 years 3 months 3 days	7 years 7 months 2 days
Long | Reverse mortgages
Securities, Available-for-sale [Line Items]
Current Principal		$ 923	$ 31,527
Unamortized Premium (Discount)		36	2,620
Debt Securities, Available-for-Sale, Amortized Cost		959	34,147
Gross Unrealized Gains		0	306
Gross Unrealized Losses		(44)	(1,329)
Securities, at fair value(1)(2)		$ 915	$ 33,124
Long | Reverse mortgages | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.39%	6.82%
Weighted Average Yield		2.66%	3.49%
Weighted average life		2 years 7 months 24 days	4 years 6 months 25 days
Long | Interest only securities
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 11,201	$ 12,430
Gross Unrealized Gains		1,654	1,295
Gross Unrealized Losses		(188)	(508)
Securities, at fair value(1)(2)		$ 12,667	$ 13,217
Long | Interest only securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		1.13%	1.11%
Weighted Average Yield		12.17%	11.57%
Weighted average life		6 years 10 months 13 days	7 years 3 days
Long | Non-Agency RMBS
Securities, Available-for-sale [Line Items]
Current Principal		$ 307,317	$ 184,120
Unamortized Premium (Discount)		(77,252)	(68,364)
Debt Securities, Available-for-Sale, Amortized Cost		230,065	115,756
Gross Unrealized Gains		26,694	14,551
Gross Unrealized Losses		(6,060)	(6,716)
Securities, at fair value(1)(2)		$ 250,699	$ 123,591
Long | Non-Agency RMBS | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		5.08%	4.96%
Weighted Average Yield		8.48%	9.13%
Weighted average life		4 years 2 months 15 days	3 years 9 months 10 days
Long | CMBS
Securities, Available-for-sale [Line Items]
Current Principal		$ 70,771	$ 81,490
Unamortized Premium (Discount)		(28,693)	(32,979)
Debt Securities, Available-for-Sale, Amortized Cost		42,078	48,511
Gross Unrealized Gains		1,258	1,697
Gross Unrealized Losses		(13,740)	(13,493)
Securities, at fair value(1)(2)		$ 29,596	$ 36,715
Long | CMBS | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		3.75%	3.89%
Weighted Average Yield		10.45%	10.98%
Weighted average life		4 years 3 months	4 years 6 months 10 days
Long | Non-Agency IOs
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 167,639	$ 83,215
Gross Unrealized Gains		9,943	9,745
Gross Unrealized Losses		(15,472)	(4,417)
Securities, at fair value(1)(2)		$ 162,110	$ 88,543
Long | Non-Agency IOs | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		0.60%	0.77%
Weighted Average Yield		19.59%	15.56%
Weighted average life		2 years 10 months 20 days	5 years 2 months 1 day
Long | CLOs
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 91,230	$ 73,749
Gross Unrealized Gains		1,292	1,196
Gross Unrealized Losses		(10,097)	(7,527)
Securities, at fair value(1)(2)		$ 82,425	$ 67,418
Long | CLOs | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		2.75%	2.63%
Weighted Average Yield		16.41%	12.22%
Weighted average life		7 years 2 months 12 days	5 years 11 months 19 days
Long | Other asset-backed securities
Securities, Available-for-sale [Line Items]
Current Principal		$ 273,805	$ 212,629
Unamortized Premium (Discount)		(244,923)	(184,370)
Debt Securities, Available-for-Sale, Amortized Cost		28,882	28,259
Gross Unrealized Gains		5,113	7,226
Gross Unrealized Losses		(472)	(2)
Securities, at fair value(1)(2)		$ 33,523	$ 35,483
Long | Other asset-backed securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		2.30%	2.88%
Weighted Average Yield		22.02%	18.89%
Weighted average life		3 years 6 months 14 days	3 years 10 days
Long | Asset-backed securities, backed by consumer loans
Securities, Available-for-sale [Line Items]
Current Principal		$ 155,768	$ 152,555
Unamortized Premium (Discount)		(94,371)	(83,622)
Debt Securities, Available-for-Sale, Amortized Cost		61,397	68,933
Gross Unrealized Gains		427	1,034
Gross Unrealized Losses		(7,767)	(9,740)
Securities, at fair value(1)(2)		$ 54,057	$ 60,227
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		9.24%	10.02%
Weighted average life		1 year 7 months 20 days	1 year 7 months 2 days
Long | Corporate debt securities
Securities, Available-for-sale [Line Items]
Current Principal		$ 52,082	$ 47,416
Unamortized Premium (Discount)		(37,192)	(33,342)
Debt Securities, Available-for-Sale, Amortized Cost		14,890	14,074
Gross Unrealized Gains		935	1,276
Gross Unrealized Losses		(1,672)	(998)
Securities, at fair value(1)(2)		$ 14,153	$ 14,352
Long | Corporate debt securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		0.10%	0.11%
Weighted Average Yield		0.00%	0.00%
Weighted average life		2 years 3 months 10 days	2 years 6 months 25 days
Long | Corporate equity securities
Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost		$ 10,530	$ 17,187
Gross Unrealized Gains		2,487	1,666
Gross Unrealized Losses		(1,515)	(6,168)
Securities, at fair value(1)(2)		11,502	12,685
Long | U.S. Treasury securities
Securities, Available-for-sale [Line Items]
Current Principal		50,492	221,114
Unamortized Premium (Discount)		77	12,155
Debt Securities, Available-for-Sale, Amortized Cost		50,569	233,269
Gross Unrealized Gains		474	129
Gross Unrealized Losses		0	(6,875)
Securities, at fair value(1)(2)		$ 51,043	$ 226,523
Long | U.S. Treasury securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.09%	4.33%
Weighted Average Yield		3.94%	4.03%
Weighted average life		4 years 11 months 19 days	7 years 8 months 1 day
Short
Securities, Available-for-sale [Line Items]
Current Principal		$ (232,929)	$ (299,577)
Unamortized Premium (Discount)		(598)	(2,080)
Investment Sold, Not yet Purchased, Sale Proceeds		(233,527)	(301,657)
Gross Unrealized Gains		429	8,092
Gross Unrealized Losses		(948)	(9)
Securities sold short, at fair value		$ (234,046)	$ (293,574)
Short | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		3.97%	3.76%
Weighted Average Yield		3.92%	3.72%
Weighted average life		7 years 25 days	6 years 4 months 2 days
Short | U.S. Treasury securities
Securities, Available-for-sale [Line Items]
Current Principal		$ (230,202)	$ (273,989)
Unamortized Premium (Discount)		(636)	78
Investment Sold, Not yet Purchased, Sale Proceeds		(230,838)	(273,911)
Gross Unrealized Gains		429	5,797
Gross Unrealized Losses		(939)	(9)
Securities sold short, at fair value		$ (231,348)	$ (268,123)
Short | U.S. Treasury securities | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		4.02%	4.11%
Weighted Average Yield		3.95%	4.08%
Weighted average life		7 years 1 month 20 days	6 years 11 months 1 day
Short | European sovereign bonds
Securities, Available-for-sale [Line Items]
Current Principal		$ (2,727)	$ (25,588)
Unamortized Premium (Discount)		38	(2,158)
Investment Sold, Not yet Purchased, Sale Proceeds		(2,689)	(27,746)
Gross Unrealized Gains		0	2,295
Gross Unrealized Losses		(9)	0
Securities sold short, at fair value		$ (2,698)	$ (25,451)
Short | European sovereign bonds | Weighted Average
Securities, Available-for-sale [Line Items]
Weighted Average Coupon		0.13%	0.01%
Weighted Average Yield		1.27%	0.16%
Weighted average life		3 months 29 days	2 months 4 days

[1] Ellington Financial Inc.'s Condensed 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.