(Schedule of Reverse Repurchase Agreements by Maturity) (Details) $ in Thousands		3 Months Ended	6 Months Ended	12 Months Ended
		Mar. 31, 2021	Jun. 30, 2021 USD ($) counterparty	Dec. 31, 2020 USD ($) counterparty
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements	[1]		$ 1,916,749	$ 1,496,931
Number of Counterparties with Outstanding Reverse Repurchase Agreements | counterparty			24	24
Total secured borrowings			$ 3,000,000	$ 2,300,000
Agency RMBS
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			1,428,503	921,862
Agency RMBS | 30 Days or Less
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			256,205	265,556
Agency RMBS | 31-60 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			379,356	385,141
Agency RMBS | 61-90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			222,787	174,586
Agency RMBS | 91-120 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			11,352	0
Agency RMBS | 151 to 180 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			0	59,857
Agency RMBS | 121-150 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			116,978	2,692
Agency RMBS | More Than 360 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			441,825	34,030
Credit
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			488,246	575,069
Credit | 30 Days or Less
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			15,906	37,795
Credit | 31-60 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			55,596	84,554
Credit | 61-90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			114,565	152,426
Credit | 91-120 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			27,513	89,931
Credit | 151 to 180 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			108,784	11,063
Credit | Total Credit Assets
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			25,000	94,248
Credit | 121-150 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			7,648	66,412
Credit | More Than 360 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements			$ 133,234	$ 38,640
Minimum
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.10%	0.20%
Repurchase agreements, remaining days to maturity		4 days	1 day
Maximum
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			3.75%	5.00%
Repurchase agreements, remaining days to maturity		516 days	730 days
Weighted Average
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.69%	1.20%
Repurchase agreements, remaining days to maturity			137 days	94 days
Weighted Average | Agency RMBS
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.17%	0.27%
Repurchase agreements, remaining days to maturity			121 days	57 days
Weighted Average | Agency RMBS | 30 Days or Less
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.15%	0.28%
Repurchase agreements, remaining days to maturity			13 days	17 days
Weighted Average | Agency RMBS | 31-60 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.16%	0.25%
Repurchase agreements, remaining days to maturity			45 days	44 days
Weighted Average | Agency RMBS | 61-90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.19%	0.28%
Repurchase agreements, remaining days to maturity			74 days	70 days
Weighted Average | Agency RMBS | 91-120 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.29%	0.00%
Repurchase agreements, remaining days to maturity			103 days	0 days
Weighted Average | Agency RMBS | 151 to 180 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.00%	0.32%
Repurchase agreements, remaining days to maturity			0 days	162 days
Weighted Average | Agency RMBS | 121-150 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.14%	0.27%
Repurchase agreements, remaining days to maturity			135 days	126 days
Weighted Average | Agency RMBS | More Than 360 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			0.19%	0.32%
Repurchase agreements, remaining days to maturity			271 days	252 days
Weighted Average | Non-Agency RMBS | 121-150 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase agreements, remaining days to maturity			0 days
Weighted Average | Credit
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			2.20%	2.69%
Repurchase agreements, remaining days to maturity			185 days	155 days
Weighted Average | Credit | 30 Days or Less
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			1.50%	2.11%
Repurchase agreements, remaining days to maturity			9 days	17 days
Weighted Average | Credit | 31-60 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			1.51%	2.23%
Repurchase agreements, remaining days to maturity			43 days	50 days
Weighted Average | Credit | 61-90 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			1.76%	2.11%
Repurchase agreements, remaining days to maturity			77 days	75 days
Weighted Average | Credit | 91-120 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			2.14%	2.47%
Repurchase agreements, remaining days to maturity			92 days	106 days
Weighted Average | Credit | 151 to 180 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			2.19%	2.27%
Repurchase agreements, remaining days to maturity			169 days	165 days
Weighted Average | Credit | Total Credit Assets
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			3.25%	2.99%
Repurchase agreements, remaining days to maturity			692 days	447 days
Weighted Average | Credit | 121-150 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			1.77%	4.75%
Repurchase agreements, remaining days to maturity			147 days	125 days
Weighted Average | Credit | More Than 360 Days
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Repurchase Agreements Interest Rate			2.81%	2.90%
Repurchase agreements, remaining days to maturity			296 days	289 days

[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.