Investments in Unconsolidated Entities (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated entities, at fair value	[1]	$ 141,620				$ 71,850				$ 141,620	$ 71,850
Earnings (losses) from investments in unconsolidated entities		27,344	$ 11,443	$ 5,643	$ (6,497)	3,262	$ 2,796	$ 2,354	$ 1,797	37,933	10,209
Investment in Loan Originator
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated entities, at fair value		79,500				40,600				79,500	40,600
Variable Interest Entity, Not Primary Beneficiary
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated entities, at fair value		$ 13,600				$ 28,500				$ 13,600	$ 28,500

[1] 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.