Investment in Loans Investment in Loans (Schedule of Residential Mortgage Loans: Performance) (Details) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		$ 1,414,410	$ 1,387,733
Loans, at fair value	[1]	1,442,612	1,412,426
Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		1,004,980	911,705
Loans, at fair value		1,030,709	932,203
Residential mortgage loans | Performing Financial Instruments [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		23,002	27,663
Loans, at fair value		21,572	25,323
Residential mortgage loans | Non-performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		64,710	17,757
Loans, at fair value		$ 62,343	$ 15,580

[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.