Related Party Transactions (Details)		3 Months Ended														12 Months Ended
		Dec. 31, 2020 USD ($)		Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)		Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2020 USD ($) numberOfWarrants period		Dec. 31, 2019 USD ($)		Dec. 31, 2018 USD ($) period
Related Party Transaction [Line Items]
Annual base management fee percentage																1.50%		1.50%
Base management fee to affiliate		$ 3,178,000	[1]	$ 2,981,000	$ 2,906,000	$ 2,443,000	$ 2,663,000		$ 1,942,000	$ 1,661,000	$ 1,722,000	$ 1,744,000	$ 1,830,000	$ 2,021,000	$ 1,978,000	$ 11,508,000	[1]	$ 7,988,000	[1]	$ 7,573,000	[2]
Base management fee, gross																12,600,000		10,000,000.0
Management Fee Expense, Rebates												400,000	400,000	300,000	300,000	$ 1,051,000		1,967,000	[1]
Incentive fee rate																25.00%				25.00%
Incentive Fee, Loss Carryforward		0					0					2,100,000				$ 0		0		$ 2,100,000
Incentive fee hurdle rate fixed																9.00%				9.00%
Incentive fee hurdle rate floating																3.00%				3.00%
Incentive Fee Expense		0		$ 0	$ 0	$ 0	116,000		$ 0	$ 0	$ 0	0	$ 424,000	$ 291,000	$ 0	$ 0		$ 116,000		$ 715,000
Minimum percentage of incentive fee to be paid in share																10.00%				10.00%
Termination Fee, Number Of Periods | period																2				2
Termination Fee, Period																12 months				12 months
Expense Reimbursement Period																60 days		60 days
Expense Reimbursement - Manager																$ 9,900,000		$ 10,900,000		$ 6,500,000
Accounts payable and accrued expenses												5,723,000								5,723,000
Fair Value												2,939,311,000								2,939,311,000
Real estate owned	[3],[4]	23,598,000					30,584,000									23,598,000		30,584,000
Investment in unconsolidated entities, at fair value	[3]	141,620,000					71,850,000									141,620,000		71,850,000
Securities, at fair value(1)(2)	[3],[4]	1,514,185,000					2,449,941,000									1,514,185,000		2,449,941,000
Non-controlling interests		36,357,000	[3]				39,434,000	[3]				31,337,000				36,357,000	[3]	39,434,000	[3]	31,337,000
Accrued expenses and other liabilities	[3]	18,659,000					7,753,000									18,659,000		7,753,000
Reverse repurchase agreements		1,496,931,000					2,445,300,000					1,498,849,000				1,496,931,000		2,445,300,000		1,498,849,000
Management fee rebate																				1,380,000
Other assets		2,575,000	[3]				7,563,000	[3]				15,536,000				2,575,000	[3]	7,563,000	[3]	15,536,000
Face amount of investments purchased from related party																				$ 2,900,000
Management Fee, description																				The Operating Partnership pays the Manager 1.50% per annum of total equity of the Operating Partnership calculated in accordance with U.S. GAAP as of the end of each fiscal quarter (before deductions for base management fees and incentive fees payable with respect to such fiscal quarter), provided that total equity is adjusted to exclude one-time events pursuant to changes in U.S. GAAP, as well as non-cash charges after discussion between the Manager and the Company's independent directors, and approval by a majority of the Company's independent directors in the case of non-cash charges.
Incentive fee, description																				The Manager is entitled to receive a quarterly incentive fee equal to the positive excess, if any, of (i) the product of (A) 25% and (B) the excess of (1) Adjusted Net Income (described below) for the Incentive Calculation Period (which means such fiscal quarter and the immediately preceding three fiscal quarters) over (2) the sum of the Hurdle Amounts (described below) for the Incentive Calculation Period, over (ii) the sum of the incentive fees already paid or payable for each fiscal quarter in the Incentive Calculation Period preceding such fiscal quarter.For purposes of calculating the incentive fee, "Adjusted Net Income" for the Incentive Calculation Period means the net increase in equity from operations of the Operating Partnership, after all base management fees but before any incentive fees for such period, and excluding any non-cash equity compensation expenses for such period, as reduced by any Loss Carryforward (as described below) as of the end of the fiscal quarter preceding the Incentive Calculation Period.For purposes of calculating the incentive fee, the "Loss Carryforward" as of the end of any fiscal quarter is calculated by determining the excess, if any, of (1) the Loss Carryforward as of the end of the immediately preceding fiscal quarter over (2) the Company's net increase in equity from operations (expressed as a positive number) or net decrease in equity from operations (expressed as a negative number) of the Operating Partnership for such fiscal quarter. As of December 31, 2018, there was a Loss Carryforward of $2.1 million.For purposes of calculating the incentive fee, the "Hurdle Amount" means, with respect to any fiscal quarter, the product of (i) one-fourth of the greater of (A) 9% and (B) 3% plus the 10-year U.S. Treasury rate for such fiscal quarter, (ii) the sum of (A) the weighted average gross proceeds per share of all common share and OP Unit issuances since inception of the Company and up to the end of such fiscal quarter, with each issuance weighted by both the number of shares and OP Units issued in such issuance and the number of days that such issued shares and OP Units were outstanding during such fiscal quarter, using a first-in first-out basis of accounting (i.e. attributing any share and OP Unit repurchases to the earliest issuances first) and (B) the result obtained by dividing (I) retained earnings attributable to common shares and OP Units at the beginning of such fiscal quarter by (II) the average number of common shares and OP Units outstanding for each day during such fiscal quarter, (iii) the sum of (x) the average number of common shares and LTIP Units outstanding for each day during such fiscal quarter, and (y) the average number of OP Units and OP LTIP Units outstanding for each day during such fiscal quarter. For purposes of determining the Hurdle Amount, issuances of common shares, OP LTIP Units, and OP Units (a) as equity incentive awards, (b) to the Manager as part of its base management fee or incentive fee and (c) to the Manager or any of its affiliates in privately negotiated transactions, are excluded from the calculation. The payment of the incentive fee will be in a combination of common shares and cash, provided that at least 10% of any quarterly payment will be made in common shares.
Termination fee, description																				The Management Agreement requires the Company to pay a termination fee to the Manager in the event of (1) the Company's termination or non-renewal of the Management Agreement without cause or (2) the Company's termination of the Management Agreement based on unsatisfactory performance by the Manager that is materially detrimental to the Company or (3) the Manager's termination of the Management Agreement upon a default by the Company in the performance of any material term of the Management Agreement. Such termination fee will be equal to the amount of three times the sum of (i) the average annual Quarterly Base Management Fee Amounts paid or payable with respect to the two 12-month periods ending on the last day of the latest fiscal quarter completed on or prior to the date of the notice of termination or non-renewal and (ii) the average annual Quarterly Incentive Fee Amounts paid or payable with respect to the two 12-month periods ending on the last day of the latest fiscal quarter completed on or prior to the date of the notice of termination or non-renewal.
Unpaid Principal Balance		1,417,054,000					1,387,733,000									1,417,054,000		1,387,733,000
Related Party Transaction, Purchases from Related Party																1,600,000		8,800,000
Securities Collateral relating to Reverse Repurchase Agreements		1,800,000,000					2,800,000,000					1,790,000,000				1,800,000,000		2,800,000,000		$ 1,790,000,000
Commercial mortgage loans and REO
Related Party Transaction [Line Items]
Fair Value		34,000,000.0					29,500,000					25,300,000				34,000,000.0		29,500,000		25,300,000
Reverse repurchase agreements		116,100,000					174,400,000					77,000,000.0				116,100,000		174,400,000		77,000,000.0
Corporate equity securities
Related Party Transaction [Line Items]
Fair Value												43,793,000								43,793,000
Secured notes
Related Party Transaction [Line Items]
Fair Value												10,917,000								10,917,000
Corporate debt securities
Related Party Transaction [Line Items]
Fair Value												22,392,000								22,392,000
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Accounts payable and accrued expenses	[3]	2,500,000					2,000,000.0									2,500,000		2,000,000.0
Affiliated Entity [Member] | Commercial mortgage loans and REO
Related Party Transaction [Line Items]
Accrued expenses and other liabilities	[3]						700,000											700,000
Mortgage Originator
Related Party Transaction [Line Items]
Warehouse facility, monetary amount		$ 5,000,000.0										$ 5,000,000.0				$ 5,000,000.0				$ 5,000,000.0
Interest rate		15.00%										15.00%				15.00%				15.00%
Advances made under warehouse facility		$ 0					0					$ 0				$ 0		0		$ 0
Loans purchased under commitment agreement																$ 150,000,000
Number of warrants purchased under commitment agreement | numberOfWarrants																9,329,000
Mortgage Originator | Warrants
Related Party Transaction [Line Items]
Investment in unconsolidated entities, at fair value		3,600,000														$ 3,600,000
Related Party-Consumer Loans Titled in Name of Related Party
Related Party Transaction [Line Items]
Fair value of loans held in related party trust		44,500,000					47,900,000					21,900,000				44,500,000		47,900,000		21,900,000
Purchasing Entity
Related Party Transaction [Line Items]
Fair value of loans held in related party trust		45,100,000					185,400,000					181,500,000				45,100,000		185,400,000		181,500,000
Consumer loans purchased through affiliate																115,700,000		134,400,000		166,300,000
Estimated remaining contingent purchase obligations		13,000,000.0					287,100,000					263,500,000				13,000,000.0		287,100,000		263,500,000
Related party trust - Residential Mortgage Loans and REO
Related Party Transaction [Line Items]
Fair value of loans held in related party trust		387,400,000					304,800,000					498,100,000				387,400,000		304,800,000		498,100,000
Related party mortgage originator (with flow mortgage loan purchase and sale agreement) [Member] | Non-Exchange Traded Equity Investment in Mortgage Originators [Member]
Related Party Transaction [Line Items]
Drawn down amount being guaranteed		5,300,000					400,000					2,900,000				5,300,000		400,000		2,900,000
Non-controlling interest of joint venture partner | Unrelated third party joint venture interest | Commercial mortgage loans and REO
Related Party Transaction [Line Items]
Non-controlling interests		4,100,000					3,600,000					1,400,000				4,100,000		3,600,000		1,400,000
Non-controlling interest of joint venture partner | Related party joint venture interest | Commercial mortgage loans and REO
Related Party Transaction [Line Items]
Non-controlling interests		8,900,000					7,000,000.0					4,100,000				8,900,000		7,000,000.0		4,100,000
Mortgage-related Commercial | Corporate equity securities
Related Party Transaction [Line Items]
Fair Value		33,900,000					17,300,000					$ 1,100,000				33,900,000		17,300,000		$ 1,100,000
Ownership percentage of limited liability company held as investment												15.00%								15.00%
Jepson Holdings Limited
Related Party Transaction [Line Items]
Investment in unconsolidated entities, at fair value		1,800,000					1,900,000									1,800,000		1,900,000
Corporate loan [Member]
Related Party Transaction [Line Items]
Unpaid Principal Balance		5,855,000					18,415,000									5,855,000		18,415,000
Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Unpaid Principal Balance							12,500,000											12,500,000
Long
Related Party Transaction [Line Items]
Securities, at fair value(1)(2)		1,514,185,000					2,449,941,000									1,514,185,000		2,449,941,000
Long | Non-Agency RMBS
Related Party Transaction [Line Items]
Securities, at fair value(1)(2)		201,090,000					163,136,000									201,090,000		163,136,000
Loan receivable from affiliated entity related to warehouse facility
Related Party Transaction [Line Items]
Other assets		6,100,000					8,100,000					$ 11,600,000				6,100,000		8,100,000		$ 11,600,000
Participation in multi-borrower financing facility
Related Party Transaction [Line Items]
Outstanding debt of related party		$ 192,300,000					$ 350,600,000					149,000,000.0				192,300,000		$ 350,600,000		149,000,000.0
Investment purchased from related party | Corporate debt securities
Related Party Transaction [Line Items]
Fair Value												$ 1,600,000								$ 1,600,000
Maximum | Mortgage Originator
Related Party Transaction [Line Items]
Commitment to purchase loans																$ 150,000,000
Number of warrants available for purchase under commitment agreement | numberOfWarrants																9,329,000
Note Purchase Agreement May 2019 [Member] | Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Investment Interest Rate		15.00%														15.00%
Note Purchase Agreement May 2019 [Member] | Maximum | Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Note Agreement, Lending Amount Per Agreement		$ 5,000,000.0														$ 5,000,000.0
Note Purchase Agreement July 2019 [Member] | Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Investment Interest Rate		18.00%														18.00%
Note Purchase Agreement July 2019 [Member] | Maximum | Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Note Agreement, Lending Amount Per Agreement		$ 5,000,000.0														$ 5,000,000.0
Note Purchase Agreement December 2019 [Member] | Maximum | Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Note Agreement, Lending Amount Per Agreement		$ 2,500,000														$ 2,500,000

[1] See Note 13 for further details on management fee rebates.

[2] See Note 9 for further details on management fee rebates.

[3] Ellington Financial Inc.'s Consolidated Balance Sheet includes assets and liabilities of variable interest entities it has consolidated. See Note 9 for additional details on Ellington Financial Inc.'s consolidated variable interest entities.

[4] Includes assets pledged as collateral to counterparties. See Note 11 for additional details on the Company's borrowings and related collateral.