Financial Derivatives (TBAs) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Financial derivatives–assets, at fair value-	$ 15,976	$ 15,479
Derivative Liability	14,119	24,553
Derivative Assets (Liabilities), at Fair Value, Net	1,857	(9,074)
TBA securities
Derivative [Line Items]
Notional Amount	632,368	354,077
Derivative, Cost Basis	(676,594)	(380,791)
Market Value Underlying	(677,276)	(380,754)
Derivative Assets (Liabilities), at Fair Value, Net	(682)	37
TBA securities | Long
Derivative [Line Items]
Notional Amount	291,283	149,990
Derivative, Cost Basis	294,634	155,008
Market Value Underlying	292,038	155,969
Derivative Assets (Liabilities), at Fair Value, Net	(2,596)	961
TBA securities | Short
Derivative [Line Items]
Notional Amount	923,651	504,067
Derivative, Cost Basis	(971,228)	(535,799)
Market Value Underlying	(969,314)	(536,723)
Derivative Assets (Liabilities), at Fair Value, Net	1,914	(924)
Financial Derivatives - Assets | TBA securities | Long
Derivative [Line Items]
Notional Amount	0	149,990
Derivative, Cost Basis	0	155,008
Market Value Underlying	0	155,969
Financial derivatives–assets, at fair value-	0	961
Financial Derivatives - Assets | TBA securities | Short
Derivative [Line Items]
Notional Amount	596,773	4,400
Derivative, Cost Basis	(623,051)	(4,765)
Market Value Underlying	(620,652)	(4,764)
Financial derivatives–assets, at fair value-	2,399	1
Financial Derivatives - Liabilities | TBA securities | Long
Derivative [Line Items]
Notional Amount	291,283	0
Derivative, Cost Basis	294,634	0
Market Value Underlying	292,038	0
Derivative Liability	(2,596)	0
Financial Derivatives - Liabilities | TBA securities | Short
Derivative [Line Items]
Notional Amount	326,878	499,667
Derivative, Cost Basis	(348,177)	(531,034)
Market Value Underlying	(348,662)	(531,959)
Derivative Liability	$ (485)	$ (925)