Derivative Instruments Schedule of TBA Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Financial derivatives–assets, at fair value	$ 1,732	$ 4,180
Financial derivatives–liabilities, at fair value	(20,234)	(2,047)
Derivative, Fair Value, Net	(18,502)	2,133
TBA securities- purchase contracts [Member]
Derivative [Line Items]
Derivative notional	53,800	70,447
Derivative cost basis	55,283	72,716
Market Value, Underyling	55,938	72,693
Derivative, Fair Value, Net	655	(23)
TBA securities- sale contracts [Member]
Derivative [Line Items]
Derivative notional	(303,388)	(246,955)
Derivative cost basis	(319,019)	(255,903)
Market Value, Underyling	(322,474)	(256,062)
Derivative, Fair Value, Net	(3,455)	(159)
TBA securities [Member]
Derivative [Line Items]
Derivative notional, net	(249,588)	(176,508)
Derivative cost basis	(263,736)	(183,187)
Market Value, Underyling	(266,536)	(183,369)
Derivative, Fair Value, Net	(2,800)	(182)
Derivative Financial Instruments, Assets [Member] \| TBA securities- purchase contracts [Member]
Derivative [Line Items]
Derivative notional	53,800	26,877
Derivative cost basis	55,283	27,087
Market Value, Underyling	55,938	27,135
Financial derivatives–assets, at fair value	655	48
Derivative Financial Instruments, Assets [Member] \| TBA securities- sale contracts [Member]
Derivative [Line Items]
Derivative notional	(22,333)	(82,520)
Derivative cost basis	(23,729)	(85,124)
Market Value, Underyling	(23,602)	(85,050)
Financial derivatives–assets, at fair value	127	74
Derivative Financial Instruments, Liabilities [Member] \| TBA securities- purchase contracts [Member]
Derivative [Line Items]
Derivative notional	0	43,570
Derivative cost basis	0	45,629
Market Value, Underyling	0	45,558
Financial derivatives–liabilities, at fair value	0	(71)
Derivative Financial Instruments, Liabilities [Member] \| TBA securities- sale contracts [Member]
Derivative [Line Items]
Derivative notional	(281,055)	(164,435)
Derivative cost basis	(295,290)	(170,779)
Market Value, Underyling	(298,872)	(171,012)
Financial derivatives–liabilities, at fair value	$ (3,582)	$ (233)

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Derivative notional amount.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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-Publisher FASB
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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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