Financial Highlights (Narrative) (Details)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investment Company, Financial Highlights [Abstract]
Market Based Total Return	4.35%	3.50%	(4.56%)

Total return for the period based upon the closing prices as reported by the New York Stock Exchange. Calculation of market based total return assumes the reinvestment of dividends at the closing price as reported by the New York Stock Exchange as of the ex-date.

No definition available.

Name:	efc_MarketBasedTotalReturn
Namespace Prefix:	efc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration