Investment in Loans (Schedule of Commercial Mortgage Loans) (Details) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		$ 1,441,017	$ 1,387,733
Unamortized Premium (Discount)		(174,092)	(150,821)
Loans, at fair value	[1]	$ 1,443,589	$ 1,412,426
Weighted Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Coupon		4.13%	4.23%
Weighted Average Yield		4.96%	4.01%
Weighted average life		4 years 5 months 12 days	5 years 10 months 24 days
Commercial mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		$ 303,718	$ 277,870
Unamortized Premium (Discount)		(280)	(3,302)
Amortized Cost		303,438	274,568
Gains		444	253
Losses		(582)	(62)
Loans, at fair value		$ 303,300	$ 274,759
Number of mortgage loans in process of foreclosure		1	2
Mortgage Loans in Process of Foreclosure, Amount		$ 10,700	$ 16,000
Commercial mortgage loans | Weighted Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Coupon		7.92%	7.65%
Weighted Average Yield		8.40%	8.58%
Weighted average life		1 year 1 month 17 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	$ 10,700

[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.