Non-controlling Interests (Details) - USD ($) $ in Thousands			3 Months Ended	9 Months Ended
		Mar. 02, 2020	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Noncontrolling Interest [Line Items]
Non-controlling interests	[1]			$ 37,147	$ 39,434
Non-controlling interest in Operating Partnership [Member] | Non-controlling Interest
Noncontrolling Interest [Line Items]
Operating Partnership LTIP Units Redeemed (in units)						503,988
Non-controlling interest of joint venture partner | Non-controlling Interest
Noncontrolling Interest [Line Items]
Non-controlling interests				$ 26,600	$ 25,900
Operating Partnership Units [Member]
Noncontrolling Interest [Line Items]
Operating Partnership Units, converted during period		(129,516)
Non-controlling interest in Operating Partnership [Member] | Non-controlling Interest
Noncontrolling Interest [Line Items]
Operating Partnership LTIP Units (in units)			545,716	579,729
Operating Partnership Units (in units)			177,925	48,409
Ownership Percentage				1.20%	1.60%
Noncontrolling Interest in Operating Partnerships				$ 10,400	$ 13,400

[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.