Related Party Transactions (Details) $ in Thousands		3 Months Ended				9 Months Ended				12 Months Ended
		Sep. 30, 2019 USD ($)		Sep. 30, 2018 USD ($)		Sep. 30, 2019 USD ($) period		Sep. 30, 2018 USD ($) period		Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Incentive Fee Expense				$ 424				$ 715
Annual base management fee percentage						1.50%		1.50%
Base management fee to affiliate		$ 1,942	[1]	1,830	[2]	$ 5,324	[1]	$ 5,829	[2]
Base management fee, gross		2,400				6,800
Management Fee Expense, Rebates	[1]	503				$ 1,458
Incentive fee rate						25.00%		25.00%
Incentive Fee, Loss Carryforward		0				$ 0				$ 2,100
Incentive fee hurdle rate fixed						9.00%		9.00%
Incentive fee hurdle rate floating						3.00%		3.00%
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						$ 8,200		$ 5,300
Accounts payable and accrued expenses		4,579	[3]			4,579	[3]			5,723
Fair Value										2,939,311
Real estate owned	[3]	44,423				44,423
Investment in unconsolidated entities, at fair value	[3]	70,435				70,435
Securities, at fair value		1,875,929				1,875,929
Non-controlling interests		33,521	[3]			33,521	[3]			31,337
Reverse repurchase agreements		2,056,422				2,056,422				1,498,849
Management fee rebate				$ 423				$ 950
Other assets		3,319	[3]			3,319	[3]			15,536
Face amount of investments purchased from related party										$ 2,900
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		1,230,004				1,230,004
Commercial mortgage loans and REO
Related Party Transaction [Line Items]
Fair Value		23,500				23,500				$ 25,300
Real estate owned		16,900				16,900
Reverse repurchase agreements		185,200				185,200				77,000
Corporate equity securities
Related Party Transaction [Line Items]
Fair Value										43,793
Secured notes
Related Party Transaction [Line Items]
Fair Value										10,917
Corporate debt securities
Related Party Transaction [Line Items]
Fair Value										22,392
Affiliated Entity [Member]
Related Party Transaction [Line Items]
Accounts payable and accrued expenses	[3]	1,800				1,800
Mortgage Originator
Related Party Transaction [Line Items]
Warehouse facility, monetary amount		$ 5,000				$ 5,000				$ 5,000
Interest rate		15.00%				15.00%				15.00%
Advances made under warehouse facility		$ 0				$ 0				$ 0
Related Party-Consumer Loans Titled in Name of Related Party
Related Party Transaction [Line Items]
Fair value of loans held in related party trust		38,600				38,600				21,900
Purchasing Entity
Related Party Transaction [Line Items]
Fair value of loans held in related party trust		149,900				149,900				181,500
Consumer loans purchased through affiliate						72,400				134,500
Estimated remaining contingent purchase obligations		128,100				128,100				263,500
Related party trust - Residential Mortgage Loans and REO
Related Party Transaction [Line Items]
Fair value of loans held in related party trust		332,600				332,600				498,100
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		2,600				2,600				1,400
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		6,000				6,000				4,100
Mortgage-related Commercial | Corporate equity securities
Related Party Transaction [Line Items]
Fair Value		18,900				18,900				$ 1,100
Ownership percentage of limited liability company held as investment										15.00%
Jepson Holdings Limited
Related Party Transaction [Line Items]
Investment in unconsolidated entities, at fair value		1,800				1,800
Corporate loan [Member]
Related Party Transaction [Line Items]
Unpaid Principal Balance		15,790				$ 15,790
Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Rate						15.00%
Unpaid Principal Balance		10,000				$ 10,000
Long
Related Party Transaction [Line Items]
Securities, at fair value		1,875,929				1,875,929
Long | Non-Agency RMBS
Related Party Transaction [Line Items]
Securities, at fair value		153,614				153,614
Loan receivable from affiliated entity related to warehouse facility
Related Party Transaction [Line Items]
Other assets		7,600				7,600				$ 11,600
Participation in multi-borrower financing facility
Related Party Transaction [Line Items]
Outstanding debt of related party		334,700				334,700				149,000
Investment purchased from related party | Corporate debt securities
Related Party Transaction [Line Items]
Fair Value										$ 1,600
Maximum | Corporate loan [Member] | Mortgage Originator
Related Party Transaction [Line Items]
Unpaid Principal Balance		$ 5,000				$ 5,000

[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 Condensed 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.