Investment in Loans (Schedule of Commercial Mortgage Loans) (Details) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		$ 1,387,733
Unamortized Premium (Discount)		(150,821)
Amortized Cost			$ 2,970,306
Loans, at fair value	[1]	$ 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		4.23%
Weighted Average Yield		4.01%
Weighted average life		5 years 10 months 24 days
Commercial mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance		$ 277,870
Unamortized Premium (Discount)		(3,302)
Amortized Cost		274,568
Gains		253
Losses		(62)
Loans, at fair value		$ 274,759
Number of mortgage loans in process of foreclosure		2
Mortgage Loans in Process of Foreclosure, Amount		$ 16,000
Commercial mortgage loans | Weighted Average
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Coupon		7.65%
Weighted Average Yield		8.58%
Weighted average life		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

[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.