Investment in Loans (Schedule of Commercial Mortgage Loans) (Details) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		$ 1,417,054	$ 1,387,733
Unamortized Premium (Discount)		(196,118)	(150,821)
Investments, at fair value, Cost				$ 2,970,306
Loans, at fair value	[1],[2]	$ 1,453,480	$ 1,412,426
Mortgage Loans in Process of Foreclosure, Amount				$ 9,100
Weighted Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Coupon		3.92%	4.23%
Weighted Average Yield		4.77%	4.01%
Weighted average life		4 years 5 months 26 days	5 years 10 months 24 days
Commercial mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		$ 212,716	$ 277,870
Unamortized Premium (Discount)		290	(3,302)
Investments, at fair value, Cost		213,006	274,568
Gains		479	253
Losses		(454)	(62)
Loans, at fair value		$ 213,031	$ 274,759
Number of mortgage loans in process of foreclosure		1	2
Mortgage Loans in Process of Foreclosure, Amount		$ 10,500	$ 16,000
Commercial mortgage loans | Non-performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		31,800	28,900
Loans, at fair value		$ 31,500	$ 26,500
Commercial mortgage loans | Weighted Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Coupon		8.38%	7.65%
Weighted Average Yield		8.28%	8.58%
Weighted average life		7 months 13 days	1 year 25 days
Non-accrual status [Member] | Commercial mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at fair value			$ 10,700
Non-accrual status [Member] | Commercial mortgage loans | Non-performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, at fair value		$ 31,500

[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.

[2] Includes assets pledged as collateral to counterparties. See Note 11 for additional details on the Company's borrowings and related collateral.