Non-controlling Interests (Details) - USD ($) $ in Thousands			3 Months Ended		12 Months Ended
	Dec. 12, 2018	Jan. 02, 2013	Mar. 31, 2019		Dec. 31, 2018	Dec. 31, 2017
Noncontrolling Interest [Line Items]
Non-controlling interests(1)			$ 30,225	[1]	$ 31,337
Non-controlling interest in Operating Partnership [Member] | Non-controlling Interest
Noncontrolling Interest [Line Items]
Operating Partnership Units Issued		212,000
Operating Partnership LTIP Units Issued (in units)	17,383
Operating Partnership LTIP Units Redeemed (in units)					503,988
Operating Partnership LTIP Units Distributed (in units)					503,988
Operating Partnership LTIP Units (in units)			521,371		521,371
Operating Partnership Units (in units)			212,000		212,000
Ownership Percentage			2.40%		2.40%	0.70%
Noncontrolling Interest in Operating Partnerships			$ 13,900		$ 13,900
Non-controlling interest of joint venture partner | Non-controlling Interest
Noncontrolling Interest [Line Items]
Non-controlling interests(1)			$ 16,200		$ 17,300

[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.