Financial Derivatives (TBAs) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Financial derivatives–assets, at fair value-	$ 23,082	$ 15,479
Derivative Liability	19,438	24,553
Derivative Assets (Liabilities), at Fair Value, Net	3,644	(9,074)
TBA securities
Derivative [Line Items]
Notional Amount	(733,730)	(354,077)
Derivative, Cost Basis	(777,970)	(380,791)
Market Value Underlying	(778,637)	(380,754)
Derivative Assets (Liabilities), at Fair Value, Net	(667)	37
TBA securities | Long
Derivative [Line Items]
Notional Amount	(184,890)	(149,990)
Derivative, Cost Basis	188,513	155,008
Market Value Underlying	184,599	155,969
Derivative Assets (Liabilities), at Fair Value, Net	(3,914)	961
TBA securities | Short
Derivative [Line Items]
Notional Amount	(918,620)	(504,067)
Derivative, Cost Basis	(966,483)	(535,799)
Market Value Underlying	(963,236)	(536,723)
Derivative Assets (Liabilities), at Fair Value, Net	3,247	(924)
Financial Derivatives - Assets | TBA securities | Long
Derivative [Line Items]
Notional Amount	(10,000)	(149,990)
Derivative, Cost Basis	10,039	155,008
Market Value Underlying	10,040	155,969
Financial derivatives–assets, at fair value-	1	961
Financial Derivatives - Assets | TBA securities | Short
Derivative [Line Items]
Notional Amount	(810,574)	(4,400)
Derivative, Cost Basis	(850,708)	(4,765)
Market Value Underlying	(847,300)	(4,764)
Financial derivatives–assets, at fair value-	3,408	1
Financial Derivatives - Liabilities | TBA securities | Long
Derivative [Line Items]
Notional Amount	174,890	0
Derivative, Cost Basis	178,474	0
Market Value Underlying	174,559	0
Derivative Liability	(3,915)	0
Financial Derivatives - Liabilities | TBA securities | Short
Derivative [Line Items]
Notional Amount	(108,046)	(499,667)
Derivative, Cost Basis	(115,775)	(531,034)
Market Value Underlying	(115,936)	(531,959)
Derivative Liability	$ (161)	$ (925)