Counterparty Risk (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2020
Risks and Uncertainties [Abstract]
Financial Instruments transferred as collateral for repurchase agreements	$ 2,763,000		$ 1,790,000	$ 1,831,000
Concentration risk threshold	15.00%		15.00%
Unencumbered investments held in custody			$ 13,300
Cash and cash equivalents	$ 72,302	[1]	44,656	$ 111,647	[1]
Pledged Financial Instruments, Not Separately Reported, Securities For Repurchase Agreements Unsettled			$ 86,700

[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.