Investment in Loans (Schedule of Consumer Loans) (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended	12 Months Ended
		Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance			$ 1,414,410	$ 1,387,733
Unamortized Premium (Discount)			(202,583)	(150,821)
Loans, at fair value	[1]		$ 1,442,612	$ 1,412,426
Weighted Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted average life			4 years 4 months 17 days	5 years 10 months 24 days
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair value of charged-off loans			$ 600	$ 600
Unpaid Principal Balance			150,062	179,743
Unamortized Premium (Discount)			7,347	5,027
Amortized Cost			157,409	184,770
Gains			1,430	2,561
Losses			(6,230)	(377)
Loans, at fair value			$ 152,609	$ 186,954
Consumer loans | Weighted Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted average life		9 months 25 days	10 months 17 days
Delinquency (Days)			4 days	4 days

[1] 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.