Dynex Capital (DX) 10-Q 3 May 21 2021 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document and Entity Information - $ / shares	3 Months Ended
	Mar. 31, 2021	Apr. 30, 2021	Dec. 31, 2020
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	1-9819
Entity Registrant Name	DYNEX CAPITAL, INC.
Entity Incorporation, State or Country Code	VA
Entity Tax Identification Number	52-1549373
Entity Address, Address Line One	4991 Lake Brook Drive
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Glen Allen,
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	23060-9245
City Area Code	(804)
Local Phone Number	217-5800
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		30,879,569
Common Stock, Par or Stated Value Per Share	$ 0.01		$ 0.01
Entity Central Index Key	0000826675
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	DX
Security Exchange Name	NYSE
Series B Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	7.625% Series B Cumulative Redeemable Preferred Stock, par value $0.01 per share
Series C Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	6.900% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock, par value $0.01 per share
Trading Symbol	DXPRC
Security Exchange Name	NYSE

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets [Abstract]
Cash	$ 328,936	$ 295,602
Cash collateral posted to counterparties	49,180	14,758
Mortgage-backed securities (including pledged of $2,173,333 and $2,467,859, respectively), at fair value	2,380,373	2,596,255
Mortgage loans held for investment, at fair value	5,749	6,264
Receivable for sales pending settlement	5,067	150,432
Derivative assets	109,746	11,342
Accrued interest receivable	15,480	14,388
Other assets, net	6,577	6,394
Total assets	2,901,108	3,095,435
Liabilities:
Repurchase agreements	2,032,089	2,437,163
Payable for purchases pending settlement	24,455	5
Derivative liabilities	19,866	1,634
Derivative Asset, Collateral, Obligation to Return Cash, Offset	83,776	7,681
Accrued interest payable	418	1,410
Accrued dividends payable	5,639	5,814
Other liabilities	3,589	8,275
Total liabilities	2,169,832	2,461,982
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, par value $0.01 per share; 50,000,000 shares authorized; 4,460,000 and 7,248,330 shares issued and outstanding, respectively ($111,500 and $181,208 aggregate liquidation preference, respectively)	107,843	174,564
Common stock, par value $0.01 per share, 90,000,000 shares authorized; 30,879,569 and 23,697,970 shares issued and outstanding, respectively	309	237
Additional paid-in capital	997,326	869,495
Accumulated other comprehensive income	15,105	80,261
Accumulated deficit	(389,307)	(491,104)
Total shareholders’ equity	731,276	633,453
Total liabilities and shareholders’ equity	$ 2,901,108	$ 3,095,435

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest income	$ 13,892	$ 39,822
Interest expense	(1,633)	(22,101)
Net interest income	12,259	17,721
Gain on sale of investments, net	4,697	84,783
Loss on investments, net	(980)	(372)
Gain (loss) on derivative instruments, net	(107,801)	195,567
Other operating expense, net	(380)	(423)
General and administrative expenses:
Compensation and benefits	(3,096)	(2,163)
Other general and administrative	(2,372)	(2,458)
Net income (loss)	117,929	(98,479)
Preferred stock dividends	(2,559)	(3,841)
Preferred stock redemption charge	2,987	3,914
Net income (loss) to common shareholders	112,383	(106,234)
Other comprehensive income:
Unrealized (loss) gain on available-for-sale investments, net	(60,459)	157,755
Reclassification adjustment for realized gain on sale of available-for-sale investments, net	(4,697)	(84,783)
Total other comprehensive (loss) income	(65,156)	72,972
Comprehensive income (loss) to common shareholders	$ 47,227	$ (33,262)
Net income (loss) per common share-basic and diluted	$ 4.20	$ (4.63)
Weighted average common shares-basic and diluted	26,788,693	22,963,084

Consolidated Statements of Shar

Consolidated Statements of Shareholders' Equity Statement - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock	Preferred StockCumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock Including Additional Paid in Capital	Preferred Stock Including Additional Paid in CapitalCumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common StockCumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in Capital	Additional Paid-in CapitalCumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss)Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Deficit	Accumulated DeficitCumulative Effect, Period of Adoption, Adjustment	Accumulated DeficitCumulative Effect, Period of Adoption, Adjusted Balance
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption accounting standard 2019-05	$ 582,988	$ (548)	$ 582,440			$ 162,807	$ 162,807	$ 229	$ 229	$ 858,347	$ 858,347	$ 173,806	$ 173,806	$ (612,201)	$ (548)	$ (612,749)
Balance, Preferred shares outstanding at Dec. 31, 2019				6,788,330	6,788,330
Balance, Common shares outstanding at Dec. 31, 2019								22,945,993	22,945,993
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issuance, shares				4,460,000
Stock Redeemed or Called During Period, Shares				(4,000,000)
Restricted stock granted, net of amortization								67,511
Stock Repurchased During Period, Shares								(18,782)
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation								(12,744)
Balance, Preferred shares outstanding at Mar. 31, 2020				7,248,330
Balance, Common shares outstanding at Mar. 31, 2020								22,981,978
Balance at Dec. 31, 2019	582,988	(548)	582,440			162,807	162,807	$ 229	$ 229	858,347	858,347	173,806	173,806	(612,201)	(548)	(612,749)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption accounting standard 2019-05	550,607	(548)	582,440			174,709	162,807	230	229	858,203	858,347	246,778	173,806	(729,313)	(548)	(612,749)
Balance at Dec. 31, 2019	(582,988)	$ 548	$ (582,440)			(162,807)	$ (162,807)	(229)	$ (229)	(858,347)	$ (858,347)	(173,806)	$ (173,806)	612,201	$ 548	$ 612,749
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issuance, value	107,988					107,988
Stock Redeemed or Called During Period, Value	(100,000)					(96,086)
Preferred stock redemption charge	(3,914)													(3,914)
Restricted stock granted, net of amortization	307							1		306
Stock Repurchased During Period, Value	(206)							0		(206)
Adjustments for tax withholding on share-based compensation	(235)							0		(235)
Stock issuance costs	(9)									(9)
Net income (loss)	(98,479)													(98,479)
Dividends on preferred stock	(3,841)													(3,841)
Dividends on common stock	(10,330)													(10,330)
Other Comprehensive Income (Loss), Net of Tax	72,972											72,972
Balance at Mar. 31, 2020	550,607					174,709		230		858,203		246,778		(729,313)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption accounting standard 2019-05	550,607					174,709		230		858,203		246,778		(729,313)
Cumulative effect of adoption accounting standard 2019-05	$ 633,453					174,564		$ 237		869,495		80,261		(491,104)
Balance, Preferred shares outstanding at Dec. 31, 2020	7,248,330			7,248,330
Balance, Common shares outstanding at Dec. 31, 2020	23,697,970							23,697,970
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issuance, shares								7,187,500
Stock Redeemed or Called During Period, Shares				(2,788,330)
Restricted stock granted, net of amortization								16,722
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation								(22,623)
Balance, Preferred shares outstanding at Mar. 31, 2021	4,460,000			4,460,000
Balance, Common shares outstanding at Mar. 31, 2021	30,879,569							30,879,569
Balance at Dec. 31, 2020	$ 633,453					174,564		$ 237		869,495		80,261		(491,104)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption accounting standard 2019-05	633,453					107,843		309		997,326		15,105		(389,307)
Balance at Dec. 31, 2020	(633,453)					(174,564)		(237)		(869,495)		(80,261)		491,104
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issuance, value	128,150							72		128,078
Stock Redeemed or Called During Period, Value	(69,708)					(66,721)
Preferred stock redemption charge	(2,987)													(2,987)
Restricted stock granted, net of amortization	451							0		451
Adjustments for tax withholding on share-based compensation	(428)							0		(428)
Stock issuance costs	(270)									(270)
Net income (loss)	117,929													117,929
Dividends on preferred stock	(2,559)													(2,559)
Dividends on common stock	(10,586)													(10,586)
Other Comprehensive Income (Loss), Net of Tax	(65,156)											(65,156)
Balance at Mar. 31, 2021	731,276					107,843		309		997,326		15,105		(389,307)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adoption accounting standard 2019-05	$ 731,276					$ 107,843		$ 309		$ 997,326		$ 15,105		$ (389,307)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net income (loss)	$ 117,929	$ (98,479)
Adjustments to reconcile net income (loss) to cash provided by operating activities:
(Gain) loss on derivative instruments, net	(107,801)	195,567
Gain on sale of investments, net	(4,697)	(84,783)
Loss on investments, net	980	372
Amortization of investment premiums, net	30,161	33,118
Other amortization and depreciation, net	599	499
Stock-based compensation expense	452	307
(Increase) decrease in accrued interest receivable	(1,092)	3,105
Decrease in accrued interest payable	(992)	(5,979)
Change in other assets and liabilities, net	(5,350)	254
Net cash provided by operating activities	30,189	43,981
Investing activities:
Purchase of investments	(68,543)	(155,594)
Principal payments received on investments	118,022	140,032
Proceeds from sales of investments	220,194	487,464
Principal payments received on mortgage loans held for investment	488	615
Net receipts (payments) on derivatives, including terminations	52,079	(187,822)
Increase (Decrease) Cash Collateral from Counterparties	76,095	3,185
Net cash provided by investing activities	398,335	287,880
Financing activities:
Borrowings under repurchase agreements	4,494,067	16,555,552
Repayments of repurchase agreement borrowings	(4,899,141)	(16,899,794)
Principal payments on non-recourse collateralized financing	(118)	(569)
Proceeds from issuance of preferred stock	0	107,988
Proceeds from issuance of common stock	128,150	0
Payments for Repurchase of Redeemable Preferred Stock	(69,708)	(100,000)
Cash paid for stock issuance costs	(270)	0
Payments for Repurchase of Common Stock	0	206
Payments related to tax withholding for stock-based compensation	(428)	(235)
Dividends paid	(13,320)	(15,027)
Net cash used in financing activities	(360,768)	(352,291)
Net increase (decrease) in cash and cash posted to counterparties	67,756	(20,430)
Cash and cash posted to counterparties at beginning of period	310,360	136,230
Cash and cash posted to counterparties at end of period	378,116	115,800
Supplemental Disclosure of Cash Activity:
Cash paid for interest	$ 2,619	$ 28,074

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Mortgage-backed securities (including pledged of $2,173,333 and $2,467,859, respectively), at fair value	$ 2,173,333	$ 2,467,859
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Preferred Stock, Shares Outstanding	4,460,000	7,248,330
Preferred Stock, Shares Issued	4,460,000	7,248,330
Preferred Stock, Liquidation Preference, Value	$ 111,500	$ 181,208
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	90,000,000	90,000,000
Common Stock, Shares, Issued	30,879,569	23,697,970
Common Stock, Shares, Outstanding	30,879,569	23,697,970
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies (Notes)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization Dynex Capital, Inc. (“Company”) was incorporated in the Commonwealth of Virginia on December 18, 1987 and commenced operations in February 1988. The Company is an internally managed mortgage real estate investment trust, or mortgage REIT, which primarily earns income from investing on a leveraged basis in debt securities, the majority of which are specified pools of Agency mortgage-backed securities (“MBS”) consisting of commercial MBS (“CMBS”), residential MBS (“RMBS”), and CMBS interest-only (“IO”) securities and non-Agency MBS, which consist mainly of CMBS IO. Agency MBS have a guaranty of principal payment by a U.S. government-sponsored entity (“GSE”) such as Fannie Mae and Freddie Mac, which are in conservatorship and are currently supported by a senior preferred stock purchase agreement from the U.S. Treasury. Non-Agency MBS are issued by non-governmental enterprises and do not have a guaranty of principal payment. The Company also invests in other types of mortgage-related securities, such as to-be-announced securities (“TBAs” or “TBA securities”). Basis of Presentation The accompanying unaudited consolidated financial statements of the Company and its subsidiaries (together, “Dynex” or, as appropriate, the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions to the Quarterly Report on Form 10-Q and Article 10, Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (the “SEC”). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all significant adjustments, consisting of normal recurring accruals, considered necessary for a fair presentation of the consolidated financial statements have been included. Operating results for the three months ended March 31, 2021 are not necessarily indicative of the results that may be expected for any other interim periods or for the entire year ending December 31, 2021. The unaudited consolidated financial statements included herein should be read in conjunction with the audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (the “2020 Form 10-K”) filed with the SEC. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements as well as the reported amounts of revenue and expenses during the reported period. Actual results could differ from those estimates. The most significant estimates used by management include, but are not limited to, amortization of premiums and discounts and fair value measurements of its investments. These items are discussed further below within this note to the consolidated financial statements. The Company believes the estimates and assumptions underlying the consolidated financial statements included herein are reasonable and supportable based on the information available as of March 31, 2021; however, the uncertainty over the impact that the COVID-19 pandemic may continue to have on the global economy and on the Company’s business makes any estimates and assumptions inherently less certain than they would be absent the current and potential impacts of COVID-19. The COVID-19 pandemic and resulting emergency measures have led (and may continue to lead) to significant disruptions in the global capital markets and supply chains as well as the economy of the U.S. and other countries impacted by COVID-19. In particular, as part of the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act passed by the U.S. Congress, which includes assistance to homeowners and renters, both Fannie Mae and Freddie Mac have implemented mortgage forbearance policies that allow borrowers to delay their mortgage payments for up to 18 months and placed a moratorium on foreclosures on single-family homes until June 30, 2021. The impact of high levels of forbearance on the Company’s MBS could range from immaterial to significant depending upon not only actual losses incurred on underlying loans but also future public policy choices and actions by the GSEs, their regulator the Federal Housing Finance Agency (“FHFA”), the U.S. Federal Reserve (“Federal Reserve”), and federal and state governments. The nature and timing of any such future public policy choices and actions are unpredictable, including the potential impact on MBS prices and prepayment speeds. Though these supportive actions have helped cushion the economic damage from the disruption of the pandemic to date, the Company can give no assurance as to how, in the long term, these and other actions by the U.S. government and GSEs will affect the efficiency, liquidity and stability of the financial and mortgage markets. Reclassifications Certain items on the Company’s consolidated balance sheet as of December 31, 2020 have been reclassified to conform to the current period’s presentation. In the Company’s 2020 Form 10-K, restricted cash on the consolidated balance sheet as of December 31, 2020 consisted of the cash collateral posted by the Company to its counterparties to cover initial and variation margin related to its financing and derivative instruments, net of any cash collateral received by the Company from its counterparties. Restricted cash has been renamed “cash collateral posted to counterparties” within total assets, and cash collateral of $7,681 posted by counterparties as of December 31, 2020 has been reclassified to “cash collateral posted by counterparties” within total liabilities. Consolidation and Variable Interest Entities The consolidated financial statements include the accounts of the Company and the accounts of its majority owned subsidiaries and variable interest entities (“VIE”) for which it is the primary beneficiary. All intercompany accounts and transactions have been eliminated in consolidation. The Company consolidates a VIE if the Company is determined to be the VIE’s primary beneficiary, which is defined as the party that has both: (i) the power to control the activities that most significantly impact the VIE’s financial performance and (ii) the right to receive benefits or absorb losses that could potentially be significant to the VIE. The Company reconsiders its evaluation of whether to consolidate a VIE on an ongoing basis, based on changes in the facts and circumstances pertaining to the VIE. Though the Company invests in Agency and non-Agency MBS which are generally considered to be interests in VIEs, the Company does not consolidate these entities because it does not meet the criteria to be deemed a primary beneficiary. The Company consolidates a securitization trust, which has residential mortgage loans included in “mortgage loans held for investment” on its consolidated balance sheet, of which a portion is pledged as collateral for one remaining non-recourse collateralized bond classified within “other liabilities” on its consolidated balance sheet. The Company owns the subordinate class in the trust and has been deemed the primary beneficiary. Income Taxes The Company has elected to be taxed as a real estate investment trust (“REIT”) under the Internal Revenue Code of 1986 and the corresponding provisions of state law. To qualify as a REIT, the Company must meet certain tests including investing in primarily real estate-related assets and the required distribution of at least 90% of its annual REIT taxable income to shareholders after consideration of its net operating loss (“NOL”) carryforward and not including taxable income retained in its taxable subsidiaries. As a REIT, the Company generally will not be subject to federal income tax on the amount of its income or capital gains that is distributed as dividends to shareholders. The Company assesses its tax positions for all open tax years and determines whether the Company has any material unrecognized liabilities and records these liabilities, if any, to the extent they are deemed more likely than not to have been incurred. Net Income (Loss) Per Common Share The Company calculates basic net income per common share by dividing net income to common shareholders for the period by weighted-average shares of common stock outstanding for that period. The Company did not have any potentially dilutive securities outstanding during the three months ended March 31, 2021 or March 31, 2020. The Company currently has unvested service-based restricted stock issued and outstanding. Holders of unvested shares of restricted stock are eligible to receive non-forfeitable dividends. As such, unvested shares of restricted stock are considered participating securities and therefore are included in the computation of basic net income per common share using the two-class method. Upon vesting, restrictions on transfer expire on each share of restricted stock, and each such share represents one unrestricted share of common stock. Because the Company’s 6.900% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock (the “Series C Preferred Stock”) is redeemable at the Company’s option for cash only and convertible into shares of common stock only upon a change of control of the Company (and subject to other circumstances) as described in Article IIIC of the Company’s Articles of Amendment to the Restated Articles of Incorporation (the “Restated Articles of Incorporation, as amended”), the effect of those shares and their related dividends were excluded from the calculation of diluted net income per common share for the periods presented. Cash Cash includes unrestricted demand deposits at highly rated financial institutions. The Company’s cash balances fluctuate throughout the year and may exceed Federal Deposit Insurance Company insured limits from time to time. Although the Company bears risk to amounts in excess of those insured by the FDIC, it does not anticipate any losses as a result due to the financial position and creditworthiness of the depository institutions in which those deposits are held. Cash Collateral Posted To/By Counterparties Cash collateral posted to/by counterparties represents amounts pledged/received to cover initial and variation margin related to the Company’s financing and derivative instruments. The following table provides a reconciliation of cash and cash posted to counterparties reported on the Company's consolidated balance sheet as of the period indicated that sum to the total of the same such amounts shown on the Company’s consolidated statement of cash flows for the three months ended March 31, 2021: March 31, 2021 Cash $ 328,936 Cash collateral posted to counterparties 49,180 Total cash and cash posted to counterparties shown on consolidated statement of cash flows $ 378,116 Mortgage-Backed Securities The Company’s MBS are recorded at fair value on the Company’s consolidated balance sheet. MBS purchased prior to January 1, 2021 are designated as available for sale (“AFS”) with changes in fair value reported in other comprehensive income (“OCI”) as an unrealized gain (loss) until the investment is sold or matures. Upon the sale of an AFS security, any unrealized gain or loss is reclassified out of accumulated other comprehensive income (“AOCI”) into net income as a realized “gain (loss) on sale of investments, net” using the specific identification method. Effective January 1, 2021, the Company elected the fair value option for all MBS purchased on or after that date with changes in fair value reported in net income as “gain (loss) on investments, net”. Management is electing the fair value option so that GAAP net income will reflect the changes in fair value for its future purchases of MBS in a manner consistent with the presentation and timing of the changes in fair value of its derivative instruments. Electing the fair value option is increasing as an industry trend for mortgage REITs who have not elected cash flow hedge accounting. “Gain (loss) on investments, net”, which was titled “fair value adjustments, net” in prior reporting periods, also includes changes in fair value for mortgage loans held for investment for which the Company elected the fair value option effective January 1, 2020. Interest Income, Premium Amortization, and Discount Accretion. Interest income on MBS is accrued based on the outstanding principal balance (or notional balance in the case of interest-only, or “IO” securities) and their contractual terms. Premiums or discounts associated with the purchase of Agency MBS as well as any non-Agency MBS are amortized or accreted into interest income over the projected life of such securities using the effective yield method, and adjustments to premium amortization and discount accretion are made for actual cash payments. The Company’s projections of future cash payments are based on input and analysis received from external sources and internal models and include assumptions about the amount and timing of loan prepayment rates, fluctuations in interest rates, credit losses, and other factors. On at least a quarterly basis, the Company reviews and makes any necessary adjustments to its cash flow projections and updates the yield recognized on these assets. The Company does not currently hold any non-Agency MBS that were purchased at a discount with credit ratings of less than ‘AA’ or not rated by any of the nationally recognized credit rating agencies at the time of purchase. Determination of MBS Fair Value. The Company estimates the fair value of the majority of its MBS based upon prices obtained from pricing services and broker quotes. The remainder of the Company’s MBS are valued by discounting the estimated future cash flows derived from cash flow models that utilize information such as the security’s coupon rate, estimated prepayment speeds, expected weighted average life, collateral composition, estimated future interest rates, expected losses, and credit enhancements as well as certain other relevant information. Please refer to Note 5 for further discussion of MBS fair value measurements. Allowance for Credit Losses. On at least a quarterly basis, the Company evaluates any MBS designated as AFS with a fair value less than its amortized cost for credit losses. If the difference between the present value of cash flows expected to be collected on the MBS is less than its amortized cost, the difference is recorded as an allowance for credit loss through net income up to and not exceeding the amount that the amortized cost exceeds current fair value. Subsequent changes in credit loss estimates are recognized in earnings in the period in which they occur. Because the majority of the Company’s investments are higher credit quality and most are guaranteed by a GSE, the Company is not likely to have an allowance for credit losses related to its MBS recorded on its consolidated balance sheet. Repurchase Agreements The Company’s repurchase agreements, which are used to finance its purchases of MBS, are accounted for as secured borrowings under which the Company pledges its securities as collateral to secure a loan, which is equal in value to a specified percentage of the estimated fair value of the pledged collateral. The Company retains beneficial ownership of the pledged collateral, which is disclosed parenthetically on the Company’s consolidated balance sheets. At the maturity of a repurchase agreement, the Company is required to repay the loan and concurrently receives back its pledged collateral from the lender or, with the consent of the lender, the Company may renew the agreement at the then prevailing financing rate. A repurchase agreement lender may require the Company to pledge additional collateral in the event of a decline in the fair value of the collateral pledged. Repurchase agreement financing is recourse to the Company and the assets pledged. Most of the Company’s repurchase agreements are based on the September 1996 version of the Bond Market Association Master Repurchase Agreement, which generally provides that the lender, as buyer, is responsible for obtaining collateral valuations from a generally recognized source agreed to by both the Company and the lender, or, in an instance when such source is not available, the value determination is made by the lender. Derivative Instruments As of March 31, 2021, the Company’s derivative instruments include U.S. Treasury futures, options on U.S. Treasury futures, options on interest rate swaps (“swaptions”) and TBA securities, which are forward contracts for the purchase or sale of Agency RMBS on a non-specified pool basis. Derivative instruments are reported at their fair value on the Company’s consolidated balance sheet as derivative assets if in a gain position or as derivative liabilities if in a loss position, at the end of the period reported. All periodic interest benefits/costs and changes in fair value of derivative instruments, including gains and losses realized upon termination, maturity, or settlement are recorded in “gain (loss) on derivative instruments, net” on the Company’s consolidated statement of comprehensive income (loss). Cash receipts and payments related to derivative instruments are classified in the investing activities section of the consolidated statements of cash flows in accordance with the underlying nature or purpose of the derivative transactions. The Company currently has short positions in U.S. Treasury futures contracts, which are valued based on exchange pricing with daily margin settlements. The Company realizes gains or losses on these contracts upon expiration at an amount equal to the difference between the current fair value of the underlying asset and the contractual price of the futures contract. Daily margin exchanges for the Company’s U.S. Treasury futures are not considered legal settlement of the instrument. The Company’s options on U.S. Treasury futures provide the Company the right, but not an obligation, to buy U.S. Treasury futures at a predetermined notional amount and stated term in the future. Options on U.S. Treasury futures are valued based on exchange pricing without daily exchanges of margin amounts. The Company records the premium paid for the option contract as a derivative asset on its consolidated balance sheet and adjusts the balance for changes in fair value through “gain (loss) on derivative instruments” until the option is exercised or the contract expires. The Company may also purchase swaptions and defer the premium payment until the effective date. The premium payable and underlying swaption are accounted for as a single unit of account. A TBA security is a forward contract (“TBA contract”) for the purchase (“long position”) or sale (“short position”) of a non-specified Agency MBS at a predetermined price with certain principal and interest terms and certain types of collateral, but the particular Agency securities to be delivered are not identified until shortly before the settlement date. The Company accounts for long and short positions in TBAs as derivative instruments because the Company cannot assert that it is probable at inception and throughout the term of an individual TBA transaction that its settlement will result in physical delivery of the underlying Agency RMBS or that the individual TBA transaction will not settle in the shortest time period possible. Please refer to Note 4 for additional information regarding the Company’s derivative instruments as well as Note 5 for information on how the fair value of these instruments is calculated. Share-Based Compensation Pursuant to the Company’s 2020 Stock and Incentive Plan (the “2020 Plan”), the Company may grant share-based compensation to eligible employees, non-employee directors or consultants or advisors to the Company, including restricted stock awards, stock options, stock appreciation rights, performance-based and service-based restricted stock units, and performance cash awards. Currently, the Company has shares of restricted stock issued and outstanding which are treated as equity awards and recorded at their fair value which is measured using the closing stock price on the date of the grant. The compensation cost is recognized over the vesting period with a corresponding credit to shareholders’ equity using the straight-line method. The Company does not estimate forfeiture rates, but adjusts for actual forfeitures in the periods in which they occur. The Company does not currently have any share-based compensation issued or outstanding other than restricted stock issued to its employees, officers, and directors. Contingencies In the normal course of business, there may be various lawsuits, claims, and other contingencies pending against the Company. On a quarterly basis, the Company evaluates whether to establish provisions for estimated losses from those matters. The Company recognizes a liability for a contingent loss when: (a) the underlying causal event has occurred prior to the balance sheet date; (b) it is probable that a loss has been incurred; and (c) there is a reasonable basis for estimating that loss. A liability is not recognized for a contingent loss when it is only possible or remotely possible that a loss has been incurred, however, possible contingent losses shall be disclosed. If the contingent loss (or an additional loss in excess of any accrual) is at least a reasonable possibility and material, then the Company discloses a reasonable estimate of the possible loss or range of loss, if such reasonable estimate can be made. If the Company cannot make a reasonable estimate of the possible material loss, or range of loss, then that fact is disclosed. As previously disclosed in the 2020 Form 10-K, the receiver (the “Receiver”) for one of the plaintiffs awarded damages in a judgment (the "DCI Judgment") against Dynex Commercial, Inc. ("DCI"), a subsidiary of a former affiliate of the Company, filed a separate claim in May 2018 against the Company seeking payment of the damages awarded in connection with the DCI Judgment, alleging that the Company breached a litigation cost sharing agreement, as amended (the "Agreement"), that was initially entered into by the Company and DCI in December 2000. On November 21, 2019, the U.S. District Court, Northern District of Texas ("Northern District Court") granted in part and denied in part summary judgment on the Receiver’s claim and the Company’s claim for offset and recoupment. The Northern District Court found that the Company breached the Agreement and therefore must pay damages to the Receiver. The Northern District Court simultaneously granted the Company’s motion for summary judgment finding that DCI also breached the Agreement and that the Company can recover amounts due to it from DCI under the Agreement. The Receiver subsequently filed a claim for damages with the Northern District Court of approximately $12,600, while the Company filed claims for damages ranging

Commitment and Contingencies

Commitment and Contingencies	3 Months Ended
	Mar. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Contingencies Disclosure	As previously disclosed in the 2020 Form 10-K, the receiver (the “Receiver”) for one of the plaintiffs awarded damages in a judgment (the "DCI Judgment") against Dynex Commercial, Inc. ("DCI"), a subsidiary of a former affiliate of the Company, filed a separate claim in May 2018 against the Company seeking payment of the damages awarded in connection with the DCI Judgment, alleging that the Company breached a litigation cost sharing agreement, as amended (the "Agreement"), that was initially entered into by the Company and DCI in December 2000. On November 21, 2019, the U.S. District Court, Northern District of Texas ("Northern District Court") granted in part and denied in part summary judgment on the Receiver’s claim and the Company’s claim for offset and recoupment. The Northern District Court found that the Company breached the Agreement and therefore must pay damages to the Receiver. The Northern District Court simultaneously granted the Company’s motion for summary judgment finding that DCI also breached the Agreement and that the Company can recover amounts due to it from DCI under the Agreement. The Receiver subsequently filed a claim for damages with the Northern District Court of approximately $12,600, while the Company filed claims for damages ranging from $13,300 to $30,600, including interest. The Receiver filed objections (the "Objections") with the Northern District Court to, among other things, the Company recovering amounts incurred prior to entry into the Agreement and amounts incurred under the Agreement after January 31, 2006, including interest, which is the date that DCI’s corporate existence ceased under Virginia law. The Company has disputed the Receiver’s Objections, arguing, among other things, that the Receiver's Objections are not supportable under Virginia law and has further refined its damages claim to range from $15,961 based on simple interest to $22,752 based on a combination of simple and compound interest, which the Company believes is supportable under Virginia law. There have been no material developments in this matter during the three months ended March 31, 2021. After consultation with litigation counsel, the Company believes, based upon information currently available and its evaluation of Virginia law, that the likelihood of loss is not probable, and given the range of potential claims for damages by the Company to offset the Receiver's claims, the amount of possible loss cannot be reasonably estimated, and therefore, no contingent liability has been recorded.

Mortgage-Backed Securities (Not

Mortgage-Backed Securities (Notes)	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Mortgage-Backed Securities	MORTGAGE-BACKED SECURITIES The following tables present the Company’s MBS by investment type as of the dates indicated: March 31, 2021 Agency RMBS Agency CMBS CMBS IO (1) Non-Agency Other Total MBS designated as AFS: Par value $ 1,651,864 $ 234,091 $ — $ 1,354 $ 1,887,309 Unamortized premium (discount) 55,118 2,975 352,655 (370) 410,378 Amortized cost 1,706,982 237,066 352,655 984 2,297,687 Gross unrealized gain 13,646 12,551 14,200 202 40,599 Gross unrealized loss (24,473) — (979) (43) (25,495) Fair value 1,696,155 249,617 365,876 1,143 2,312,791 MBS measured at fair value through net income: Par value $ 67,692 $ — $ — $ — $ 67,692 Unamortized premium (discount) 850 — — — 850 Amortized cost 68,542 — — — 68,542 Gross unrealized gain — — — — — Gross unrealized loss (960) — — — (960) Fair value 67,582 — — — 67,582 Total as of March 31, 2021 $ 1,763,737 $ 249,617 $ 365,876 $ 1,143 $ 2,380,373 (1) The notional balance for Agency CMBS IO and non-Agency CMBS IO was $11,097,619 and $9,209,025 respectively, as of March 31, 2021. December 31, 2020 Agency RMBS Agency CMBS CMBS IO (1) Non-Agency Other Total MBS designated as AFS: Par value $ 1,839,046 $ 235,801 $ — $ 1,499 $ 2,076,346 Unamortized premium (discount) 57,997 3,152 378,940 (440) 439,649 Amortized cost 1,897,043 238,953 378,940 1,059 2,515,995 Gross unrealized gain 49,348 19,597 12,081 267 81,293 Gross unrealized loss — — (982) (51) (1,033) Fair value 1,946,391 258,550 390,039 1,275 2,596,255 MBS measured at fair value through net income: Par value $ — $ — $ — $ — $ — Unamortized premium (discount) — — — — — Amortized cost — — — — — Gross unrealized gain — — — — — Gross unrealized loss — — — — — Fair value — — — — — Total as of December 31, 2020 $ 1,946,391 $ 258,550 $ 390,039 $ 1,275 $ 2,596,255 (1) The notional balance for the Agency CMBS IO and non-Agency CMBS IO was $11,277,908 and $9,319,520, respectively, as of December 31, 2020. The majority of the Company’s MBS are pledged as collateral for the Company’s repurchase agreements which are disclosed in Note 3 . Actual maturities of MBS are affected by the contractual lives of the underlying mortgage collateral, periodic payments of principal, prepayments of principal, and the payment priority structure of the security; therefore, actual maturities are generally shorter than the securities' stated contractual maturities. The following table presents information regarding the "gain on sale of investments, net" on the Company’s consolidated statements of comprehensive income (loss) for the periods indicated: Three Months Ended March 31, 2021 2020 Proceeds Received Realized Gain Proceeds Received Realized Gain Agency RMBS-designated as AFS $ 74,829 $ 4,697 $ 1,817,350 $ 64,094 Agency CMBS-designated as AFS — — 173,684 20,689 $ 74,829 $ 4,697 $ 1,991,034 $ 84,783 The following table presents certain information for the AFS securities in an unrealized loss position as of the dates indicated: March 31, 2021 December 31, 2020 Fair Value Gross Unrealized Losses # of Securities Fair Value Gross Unrealized Losses # of Securities Continuous unrealized loss position for less than 12 months: Agency MBS $ 1,446,354 $ (25,019) 32 $ 19,266 $ (399) 19 Non-Agency MBS 5,221 (111) 5 33,417 (408) 23 Continuous unrealized loss position for 12 months or longer: Agency MBS $ 846 $ (224) 5 $ 749 $ (133) 2 Non-Agency MBS 5,029 (140) 8 2,156 (93) 5 The unrealized losses on the Company’s MBS were the result of declines in market prices and were not credit related; therefore the Company’s allowance for credit losses on its MBS designated as AFS was $0 as of March 31, 2021. The principal related to Agency MBS is guaranteed by the GSEs Fannie Mae and Freddie Mac. Although the unrealized losses are not credit related, the Company assesses its ability and intent to hold any MBS with an unrealized loss until the recovery in its value in accordance with GAAP. This assessment is based on the amount of the unrealized loss and significance of the related investment as well as the Company’s leverage and liquidity position. In addition, for its non-Agency MBS, the Company reviews the credit ratings, the credit characteristics of the mortgage loans collateralizing these securities, and the estimated future cash flows including projected collateral losses.

Repurchase Agreements (Notes)

Repurchase Agreements (Notes)	3 Months Ended
	Mar. 31, 2021
Disclosure of Repurchase Agreements [Abstract]
Repurchase agreements	REPURCHASE AGREEMENTS The Company’s repurchase agreements outstanding as of March 31, 2021 and December 31, 2020 are summarized in the following tables: March 31, 2021 December 31, 2020 Collateral Type Balance Weighted Fair Value of Balance Weighted Fair Value of Agency RMBS $ 1,499,034 0.16 % $ 1,568,623 $ 1,874,176 0.23 % $ 1,973,608 Agency CMBS 234,228 0.16 % 246,936 237,649 0.23 % 255,741 Agency CMBS IO 191,882 0.78 % 228,854 209,393 0.90 % 243,042 Non-Agency CMBS IO 106,945 1.01 % 128,920 115,945 1.28 % 136,684 Total repurchase agreements $ 2,032,089 0.26 % $ 2,173,333 $ 2,437,163 0.34 % $ 2,609,075 The amounts for fair value of collateral pledged in the table above as of December 31, 2020 include securities with an amortized cost of $141,215 which were sold but not settled as of that date, and for which the proceeds of $150,432 are recorded within “receivable for sales pending settlement” on the consolidated balance sheet. These securities collateralized $140,612 of the Company’s repurchase agreement borrowings outstanding as of December 31, 2020. The Company also had $24,455 and $5 payable to counterparties as of March 31, 2021 and December 31, 2020, respectively, for purchases pending settlement as of those respective dates. The Company had repurchase agreement borrowings outstanding with 20 different counterparties as of March 31, 2021, and its equity at risk did not exceed 5% with any counterparty as of that date. The following table provides information on the remaining term to maturity and original term to maturity for the Company’s repurchase agreements as of the dates indicated: March 31, 2021 December 31, 2020 Remaining Term to Maturity Balance Weighted WAVG Original Term to Maturity Balance Weighted WAVG Original Term to Maturity Less than 30 days $ 1,119,808 0.27 % 24 $ 1,416,608 0.37 % 53 30 to 90 days 753,223 0.28 % 42 845,394 0.31 % 35 91 to 180 days 159,058 0.17 % 14 175,161 0.22 % 13 Total $ 2,032,089 0.26 % 30 $ 2,437,163 0.34 % 44 The Company has one committed repurchase facility with Wells Fargo that has an aggregate maximum borrowing capacity of $250,000, of which it had $114,251 outstanding at a weighted average borrowing rate of 0.97% as of March 31, 2021. The maturity date for the facility is June 11, 2021. The Company is expecting to renew the facility as it has in prior periods and with similar terms. The remaining repurchase facilities available to the Company are uncommitted with no guarantee of renewal or terms of renewal. The Company’s counterparties, as set forth in the master repurchase agreement with the counterparty, require the Company to comply with various customary operating and financial covenants, including, but not limited to, minimum net worth and earnings, maximum declines in net worth in a given period, and maximum leverage requirements as well as maintaining the Company’s REIT status. In addition, some of the agreements contain cross default features, whereby default under an agreement with one lender simultaneously causes default under agreements with other lenders. To the extent that the Company fails to comply with the covenants contained in these financing agreements or is otherwise found to be in default under the terms of such agreements, the counterparty has the right to accelerate amounts due under the master repurchase agreement. The Company believes it was in full compliance with all covenants in master repurchase agreements under which there were amounts outstanding as of March 31, 2021. The Company's repurchase agreements are subject to underlying agreements with master netting or similar arrangements, which provide for the right of offset in the event of default or in the event of bankruptcy of either party to the transactions. The Company reports its repurchase agreements to these arrangements on a gross basis. The following tables present information regarding the Company's repurchase agreements as if the Company had presented them on a net basis as of March 31, 2021 and December 31, 2020: Gross Amount of Recognized Liabilities Gross Amount Offset in the Balance Sheet Net Amount of Liabilities Presented in the Balance Sheet Gross Amount Not Offset in the Balance Sheet (1) Net Amount Financial Instruments Posted as Collateral Cash Posted as Collateral March 31, 2021 Repurchase agreements $ 2,032,089 $ — $ 2,032,089 $ (2,032,089) $ — $ — December 31, 2020 Repurchase agreements $ 2,437,163 $ — $ 2,437,163 $ (2,437,163) $ — $ — (1) Amounts disclosed for collateral received by or posted to the same counterparty include cash and the fair value of MBS up to and not exceeding the net amount of the repurchase agreement liability presented in the balance sheet. The fair value of the total collateral received by or posted to the same counterparty may exceed the amounts presented. Please see Note 4

Derivatives (Notes)

Derivatives (Notes)	3 Months Ended
	Mar. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	DERIVATIVES Types and Uses of Derivatives Instruments Interest Rate Derivatives. The Company is currently using short positions in U.S. Treasury futures, put options on U.S. Treasury futures, and interest rate swaptions to mitigate the impact of changing interest rates on its book value. TBA Transactions. The Company purchases TBA securities as a means of investing in non-specified fixed-rate Agency RMBS and may also periodically sell TBA securities as a means of economically hedging its book value exposure to Agency RMBS. The Company holds long and short positions in TBA securities by executing a series of transactions, commonly referred to as “dollar roll” transactions, which effectively delay the settlement of a forward purchase (or sale) of a non-specified Agency RMBS by entering into an offsetting TBA position, net settling the paired-off positions in cash, and simultaneously entering into an identical TBA long (or short) position with a later settlement date. TBA securities purchased (or sold) for a forward settlement date are generally priced at a discount relative to TBA securities settling in the current month. This discount, often referred to as “drop income” represents the economic equivalent of net interest income (interest income less implied financing cost) on the underlying Agency security from trade date to settlement date. The Company accounts for all TBAs (whether net long or net short positions, or collectively “TBA dollar roll positions”) as derivative instruments because it cannot assert that it is probable at inception and throughout the term of an individual TBA transaction that its settlement will result in physical delivery of the underlying Agency RMBS, or that the individual TBA transaction will not settle in the shortest period possible. Gain (Loss) on Derivative Instruments, Net The table below provides detail of the Company’s “gain (loss) on derivative instruments, net” by type of derivative for the periods indicated: Three Months Ended March 31, Type of Derivative Instrument 2021 2020 Interest rate swaps $ — $ (182,181) Interest rate swaptions 57,763 (573) U.S. Treasury futures 95,647 (8,447) Options on U.S. Treasury futures 12,617 (10,727) TBA securities - long positions (58,226) 18,432 TBA securities - short positions — (12,071) Gain (loss) on derivative instruments, net $ 107,801 $ (195,567) The table below summarizes information about the carrying value by type of derivative instrument on the Company’s consolidated balance sheets as of the dates indicated: Type of Derivative Instrument Balance Sheet Location Purpose March 31, 2021 December 31, 2020 U.S. Treasury futures Derivative assets Economic hedging $ 72,723 $ — Options on U.S. Treasury futures Derivative assets Economic hedging 9,180 1,094 Interest rate swaptions Derivative assets Economic hedging 27,843 1,360 TBA securities Derivative assets Investing — 8,888 Total derivatives assets $ 109,746 $ 11,342 Interest rate swaptions Derivative liabilities Economic hedging $ — $ (107) U.S. Treasury futures Derivative liabilities Economic hedging — (1,527) TBA securities Derivative liabilities Investing (19,866) — Total derivatives liabilities $ (19,866) $ (1,634) The following table provides details on the Company’s interest rate swaptions held as of the dates indicated: Option Underlying Payer Swap Average Months to Expiration Cost Fair Value Notional Amount Average Fixed Pay Rate Average Term in Years As of March 31, 2021: 6 months or less $ 2,963 $ 14,208 $ 250,000 1.12% 10 6-9 months 3,725 13,635 250,000 1.19% 10 $ 6,688 $ 27,843 $ 500,000 1.16% As of December 31, 2020: 6 months or less $ 6,312 $ 1,161 $ 750,000 1.02% 10 6-9 months 6,688 92 500,000 1.16% 10 $ 13,000 $ 1,253 $ 1,250,000 1.07% The following table provides details on the Company’s U.S. Treasury futures and options on U.S. Treasury futures held as of the dates indicated: March 31, 2021 December 31, 2020: Notional Amount Long (Short) Fair Value Average Term to Expiration Notional Amount Long (Short) Fair Value Average Term to Expiration Options on U.S. Treasury futures $ 250,000 $ 9,180 2 months $ 500,000 $ 1,094 1 month U.S. Treasury futures (2,980,000) 72,723 3 months (825,000) (1,527) 2 months The following table summarizes information about the Company's long positions in TBA securities as of the dates indicated: March 31, 2021 December 31, 2020 Implied market value (1) $ 2,825,937 $ 1,572,949 Implied cost basis (2) 2,845,803 1,564,061 Net carrying value (3) $ (19,866) $ 8,888 (1) Implied market value represents the estimated fair value of the underlying Agency MBS as of the date indicated. (2) Implied cost basis represents the forward price to be paid for the underlying Agency MBS as of the date indicated. (3) Net carrying value is the amount included on the consolidated balance sheets within “derivative assets (liabilities)” and represents the difference between the implied market value and the implied cost basis of the TBA security as of the date indicated. Volume of Activity The tables below summarize changes in the Company’s derivative instruments for the three months ended March 31, 2021: Type of Derivative Instrument Beginning Additions Settlements, Ending Interest rate swaptions 1,250,000 — (750,000) 500,000 U.S. Treasury futures (825,000) (4,010,000) 1,855,000 (2,980,000) Options on U.S. Treasury futures 500,000 1,500,000 (1,750,000) 250,000 TBA securities 1,515,000 8,065,000 (6,780,000) 2,800,000 Offsetting The Company's derivatives are subject to underlying agreements with master netting or similar arrangements, which provide for the right of offset in the event of default or in the event of bankruptcy of either party to the transactions. The Company reports its derivative assets and liabilities subject to these arrangements on a gross basis. Please see Note 3 for information related to the Company’s repurchase agreements, which are also subject to underlying agreements with master netting or similar arrangements. The following tables present information regarding those derivative assets and liabilities subject to such arrangements as if the Company had presented them on a net basis as of March 31, 2021 and December 31, 2020: Offsetting of Assets Gross Amount of Recognized Assets Gross Amount Offset in the Balance Sheet Net Amount of Assets Presented in the Balance Sheet Gross Amount Not Offset in the Balance Sheet (1) Net Amount Financial Instruments Received as Collateral Cash Received as Collateral March 31, 2021 U.S. Treasury futures $ 72,723 $ — $ 72,723 $ — $ (26,430) $ 46,293 Options on U.S. Treasury futures 9,180 — 9,180 — — 9,180 Interest rate swaptions 27,843 — 27,843 — (27,843) — Derivative assets $ 109,746 $ — $ 109,746 $ — $ (54,273) $ 55,473 December 31, 2020 Interest rate swaptions $ 1,360 $ — $ 1,360 $ (107) $ — $ 1,253 Options on U.S. Treasury futures 1,094 — 1,094 — — 1,094 TBA securities 8,888 — 8,888 — (7,681) 1,207 Derivative assets $ 11,342 $ — $ 11,342 $ (107) $ (7,681) $ 3,554 Offsetting of Liabilities Gross Amount of Recognized Liabilities Gross Amount Offset in the Balance Sheet Net Amount of Liabilities Presented in the Balance Sheet Gross Amount Not Offset in the Balance Sheet (1) Net Amount Financial Instruments Posted as Collateral Cash Posted as Collateral March 31, 2021 TBA securities $ (19,866) — $ (19,866) $ — $ 19,866 $ — Derivative liabilities $ (19,866) $ — $ (19,866) $ — $ 19,866 $ — December 31, 2020 U.S. Treasury futures-short positions $ (1,527) — $ (1,527) $ — $ 1,527 $ — Interest rate swaptions (107) — (107) 107 — — Derivative liabilities $ (1,634) $ — $ (1,634) $ 107 $ 1,527 $ — (1) Amounts disclosed for collateral received by or posted to the same counterparty include cash and the fair value of MBS up to and not exceeding the net amount of the derivative asset or liability presented in the balance sheet. The fair value of the total collateral received by or posted to the same counterparty may exceed the amounts presented. Please refer to the consolidated balance sheets for the total fair value of financial instruments pledged as collateral for derivatives and repurchase agreements, which is shown parenthetically, and the total cash pledged or received as collateral which is disclosed in “cash collateral posted to/by counterparties.”

Fair Value of Financial Instrum

Fair Value of Financial Instruments (Notes)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	FAIR VALUE OF FINANCIAL INSTRUMENTS Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is based on the assumptions market participants would use when pricing an asset or liability and also considers all aspects of nonperformance risk, including the entity’s own credit standing, when measuring fair value of a liability. ASC Topic 820 established a valuation hierarchy of three levels as follows: • Level 1 – Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities as of the measurement date. • Level 2 – Inputs include quoted prices in active markets for similar assets or liabilities; quoted prices in inactive markets for identical or similar assets or liabilities; or inputs either directly observable or indirectly observable through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life. • Level 3 – Unobservable inputs are supported by little or no market activity. The unobservable inputs represent management’s best estimate of how market participants would price the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model. The following table presents the Company’s financial instruments that are measured at fair value on the Company’s consolidated balance sheet by their valuation hierarchy levels as of the dates indicated: March 31, 2021 December 31, 2020 Fair Value Level 1 Level 2 Level 3 Fair Value Level 1 Level 2 Level 3 Assets carried at fair value: MBS $ 2,380,373 $ — $ 2,379,230 $ 1,143 $ 2,596,255 $ — $ 2,594,980 $ 1,275 Mortgage loans held for investment 5,749 — — 5,749 6,264 — — 6,264 Derivative assets: U.S. Treasury futures $ 72,723 72,723 — — — — — — Options on U.S. Treasury futures 9,180 9,180 — — 1,094 1,094 — — Interest rate swaptions 27,843 — 27,843 — 1,360 — 1,360 — TBA securities-long positions — — — — 8,888 — 8,888 — Total assets carried at fair value $ 2,495,868 $ 81,903 $ 2,407,073 $ 6,892 $ 2,613,861 $ 1,094 $ 2,605,228 $ 7,539 Liabilities carried at fair value: U.S. Treasury futures $ — $ — $ — $ — $ 1,527 $ 1,527 $ — $ — Interest rate swaptions — — — — 107 — 107 — TBA securities-long positions 19,866 — 19,866 — — — — — Total liabilities carried at fair value $ 19,866 $ — $ 19,866 $ — $ 1,634 $ 1,527 $ 107 $ — The fair value measurements for the Company's MBS are considered Level 2 when there are substantially similar securities actively trading or for which there has been recent trading activity in their respective markets and are based on prices received from pricing services and quotes from brokers. In valuing a security, the pricing service uses either a market approach, which uses observable prices and other relevant information that is generated by market transactions of identical or similar securities, or an income approach, which uses valuation techniques to convert future amounts to a single, discounted present value amount. The Company reviews the prices it receives from its pricing sources as well as the assumptions and inputs utilized by its pricing sources for reasonableness. Examples of these observable inputs and assumptions include market interest rates, credit spreads, and projected prepayment speeds, among other things. The Company owns other non-Agency MBS and mortgage loans that are considered Level 3 assets because there has been no recent trading activity of similar instruments upon which their fair value can be measured. The fair value for these Level 3 assets is measured by discounting the estimated future cash flows derived from cash flow models using significant inputs which are determined by the Company when market observable inputs are not available. Information utilized in those pricing models include the security’s credit rating, coupon rate, estimated prepayment speeds, expected weighted average life, collateral composition, estimated future interest rates, expected credit losses, and credit enhancement as well as certain other relevant information. The Company used a constant prepayment rate assumption of 10%, default rate of 2%, loss severity of 20%, and a discount rate of 7.0% in measuring the fair value of its Level 3 assets as of March 31, 2021. Significant changes in any of these inputs in isolation may result in a significantly different fair value measurement. Level 3 assets are generally most sensitive to the default rate and severity assumptions. The activity of the Company’s Level 3 assets during the three months ended March 31, 2021 is presented in the following table: Three Months Ended March 31, 2021 Other Non-Agency MBS Mortgage Loans Balance as of beginning of period $ 1,275 $ 6,264 Change in fair value (1) (57) (22) Principal payments (145) (488) Accretion (amortization) 70 (5) Balance as of end of period $ 1,143 $ 5,749 (1) Change in fair value for mortgage loans is recorded as unrealized gain (loss) in “gain (loss) on investments, net” in net income and change in fair value for other non-Agency MBS is recorded as unrealized gain (loss) in “other comprehensive income”. U.S. Treasury futures and options on U.S. Treasury futures are valued based on closing exchange prices on these contracts and are classified accordingly as Level 1 measurements. The fair value of interest rate swaptions is based on the fair value of the underlying interest rate swap and time remaining until its expiration and is carried on the balance sheet net of any deferred premium to be paid upon expiration. The fair value of TBA securities is estimated using methods similar those used to fair value the Company’s Level 2 MBS.

Shareholders' Equity and Share-

Shareholders' Equity and Share-Based Compensation (Notes)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Shareholders' Equity and Share-based Compensation	SHAREHOLDERS’ EQUITY AND SHARE-BASED COMPENSATION Preferred Stock. The Company's articles of incorporation authorize the issuance of up to 50,000,000 shares of preferred stock, par value $0.01 per share. The Company’s Board of Directors has designated 6,600,000 shares for issuance as Series C Preferred Stock, of which the Company has 4,460,000 of such shares outstanding as of March 31, 2021. During the first quarter of 2021, the Company redeemed the remaining 2,788,330 outstanding shares of its 7.625% Series B Cumulative Redeemable Preferred Stock at an aggregate redemption price of approximately $25.15 per share, which included accumulated and unpaid dividends declared as of the redemption date February 15, 2021. The excess of the $25.00 liquidation price per share over the carrying value of the preferred stock redeemed resulted in a charge of $(2,987) to net income to common shareholders for the three months ended March 31, 2021. The Series C Preferred Stock has no stated maturity, is not subject to any sinking fund or mandatory redemption, and will remain outstanding indefinitely unless redeemed or otherwise repurchased or converted into common stock pursuant to the terms of the Series C Preferred Stock. Except under certain limited circumstances described in Article IIIC of the Company’s Restated Articles of Incorporation, as amended, the Company may not redeem the Series C Preferred Stock prior to April 15, 2025. On or after that date, the Series C Preferred Stock may be redeemed at any time and from time to time at the Company's option at a cash redemption price of $25.00 per share plus any accumulated and unpaid dividends. Because the Series C Preferred Stock is redeemable only at the option of the issuer, it is classified as equity on the Company’s consolidated balance sheet. The Series C Preferred stock pays a cumulative cash dividend equivalent to 6.900% of the $25.00 liquidation preference per share each year until April 15, 2025 upon which date and thereafter, the Company will pay cumulative cash dividends at a percentage of the $25.00 liquidation value per share equal to an annual floating rate of three-month LIBOR plus a spread of 5.461%. The Company paid its regular quarterly dividend of $0.43125 per share of Series C Preferred Stock on April 15, 2021 to shareholders of record as of April 1, 2021. Common Stock. The following table summarizes information regarding monthly dividend declarations on the Company’s common stock during the three months ended March 31, 2021: Three Months Ended March 31, 2021 Declaration Date Amount Declared Record Date Payment Date January 13, 2021 $ 0.13 January 25, 2021 February 1, 2021 February 11, 2021 0.13 February 22, 2021 March 1, 2021 March 11, 2021 0.13 March 22, 2021 April 1, 2021 Stock and Incentive Plans. The Company’s 2020 Stock and Incentive Plan reserves for issuance up to 2,300,000 common shares for eligible employees, non-employee directors, consultants, and advisors to the Company to be granted in the form of stock options, restricted stock, restricted stock units, stock appreciation rights, performance units, and performance cash awards. Awards previously granted under the 2018 Plan or any other prior equity plan will remain outstanding and valid in accordance with their terms, but no new awards will be granted under the 2018 Plan or any other prior equity plan. Total stock-based compensation expense recognized by the Company for the three months ended March 31, 2021 was $452 compared to $307 for the three months ended March 31, 2020. The following table presents a rollforward of the restricted stock activity for the periods indicated: Three Months Ended March 31, 2021 March 31, 2020 Shares Weighted Average Grant Date Fair Value Per Share Shares Weighted Average Grant Date Fair Value Per Share Restricted stock outstanding as of beginning of period 281,761 $ 14.74 119,213 $ 18.56 Granted 16,722 19.03 67,511 17.10 Vested (59,024) 18.02 (48,569) 19.02 Restricted stock outstanding as of end of period 239,459 $ 14.23 138,155 $ 17.69 As of March 31, 2021, the grant date fair value of the Company’s remaining nonvested restricted stock is $2,626 which will be amortized into compensation expense over a weighted average period of 2.1 years.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2021
Accounting Policies [Abstract]
Organization [Text Block]	OrganizationDynex Capital, Inc. (“Company”) was incorporated in the Commonwealth of Virginia on December 18, 1987 and commenced operations in February 1988. The Company is an internally managed mortgage real estate investment trust, or mortgage REIT, which primarily earns income from investing on a leveraged basis in debt securities, the majority of which are specified pools of Agency mortgage-backed securities (“MBS”) consisting of commercial MBS (“CMBS”), residential MBS (“RMBS”), and CMBS interest-only (“IO”) securities and non-Agency MBS, which consist mainly of CMBS IO. Agency MBS have a guaranty of principal payment by a U.S. government-sponsored entity (“GSE”) such as Fannie Mae and Freddie Mac, which are in conservatorship and are currently supported by a senior preferred stock purchase agreement from the U.S. Treasury. Non-Agency MBS are issued by non-governmental enterprises and do not have a guaranty of principal payment. The Company also invests in other types of mortgage-related securities, such as to-be-announced securities (“TBAs” or “TBA securities”).
Basis of Presentation [Policy Text Block]	Basis of Presentation The accompanying unaudited consolidated financial statements of the Company and its subsidiaries (together, “Dynex” or, as appropriate, the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions to the Quarterly Report on Form 10-Q and Article 10, Rule 10-01 of Regulation S-X promulgated by the Securities and Exchange Commission (the “SEC”). Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all significant adjustments, consisting of normal recurring accruals, considered necessary for a fair presentation of the consolidated financial statements have been included. Operating results for the three months ended March 31, 2021 are not necessarily indicative of the results that may be expected for any other interim periods or for the entire year ending December 31, 2021. The unaudited consolidated financial statements included herein should be read in conjunction with the audited financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020 (the “2020 Form 10-K”) filed with the SEC.
Use of Estimates [Policy Text Block]	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements as well as the reported amounts of revenue and expenses during the reported period. Actual results could differ from those estimates. The most significant estimates used by management include, but are not limited to, amortization of premiums and discounts and fair value measurements of its investments. These items are discussed further below within this note to the consolidated financial statements. The Company believes the estimates and assumptions underlying the consolidated financial statements included herein are reasonable and supportable based on the information available as of March 31, 2021; however, the uncertainty over the impact that the COVID-19 pandemic may continue to have on the global economy and on the Company’s business makes any estimates and assumptions inherently less certain than they would be absent the current and potential impacts of COVID-19. The COVID-19 pandemic and resulting emergency measures have led (and may continue to lead) to significant disruptions in the global capital markets and supply chains as well as the economy of the U.S. and other countries impacted by COVID-19. In particular, as part of the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act passed by the U.S. Congress, which includes assistance to homeowners and renters, both Fannie Mae and Freddie Mac have implemented mortgage forbearance policies that allow borrowers to delay their mortgage payments for up to 18 months and placed a moratorium on foreclosures on single-family homes until June 30, 2021. The impact of high levels of forbearance on the Company’s MBS could range from immaterial to significant depending upon not only actual losses incurred on underlying loans but also future public policy choices and actions by the GSEs, their regulator the Federal Housing Finance Agency (“FHFA”), the U.S. Federal Reserve (“Federal Reserve”), and federal and state governments. The nature and timing of any such future public policy choices and actions are unpredictable, including the potential impact on MBS prices and prepayment speeds. Though these supportive actions have helped cushion the economic damage from the disruption of the
Reclassification, Comparability Adjustment	Reclassifications Certain items on the Company’s consolidated balance sheet as of December 31, 2020 have been reclassified to conform to the current period’s presentation. In the Company’s 2020 Form 10-K, restricted cash on the consolidated balance sheet as of December 31, 2020 consisted of the cash collateral posted by the Company to its counterparties to cover initial and variation margin related to its financing and derivative instruments, net of any cash collateral received by the Company from its counterparties. Restricted cash has been renamed “cash collateral posted to counterparties” within total assets, and cash collateral of $7,681 posted by counterparties as of December 31, 2020 has been reclassified to “cash collateral posted by counterparties” within total liabilities.
Consolidation [Policy Text Block]	Consolidation and Variable Interest Entities The consolidated financial statements include the accounts of the Company and the accounts of its majority owned subsidiaries and variable interest entities (“VIE”) for which it is the primary beneficiary. All intercompany accounts and transactions have been eliminated in consolidation. The Company consolidates a VIE if the Company is determined to be the VIE’s primary beneficiary, which is defined as the party that has both: (i) the power to control the activities that most significantly impact the VIE’s financial performance and (ii) the right to receive benefits or absorb losses that could potentially be significant to the VIE. The Company reconsiders its evaluation of whether to consolidate a VIE on an ongoing basis, based on changes in the facts and circumstances pertaining to the VIE. Though the Company invests in Agency and non-Agency MBS which are generally considered to be interests in VIEs, the Company does not consolidate these entities because it does not meet the criteria to be deemed a primary beneficiary.
Income Taxes [Policy Text Block]	Income Taxes The Company has elected to be taxed as a real estate investment trust (“REIT”) under the Internal Revenue Code of 1986 and the corresponding provisions of state law. To qualify as a REIT, the Company must meet certain tests including investing in primarily real estate-related assets and the required distribution of at least 90% of its annual REIT taxable income to shareholders after consideration of its net operating loss (“NOL”) carryforward and not including taxable income retained in its taxable subsidiaries. As a REIT, the Company generally will not be subject to federal income tax on the amount of its income or capital gains that is distributed as dividends to shareholders. The Company assesses its tax positions for all open tax years and determines whether the Company has any material unrecognized liabilities and records these liabilities, if any, to the extent they are deemed more likely than not to have been incurred.
Net Income (Loss) Per Common Share	Net Income (Loss) Per Common Share The Company calculates basic net income per common share by dividing net income to common shareholders for the period by weighted-average shares of common stock outstanding for that period. The Company did not have any potentially dilutive securities outstanding during the three months ended March 31, 2021 or March 31, 2020. The Company currently has unvested service-based restricted stock issued and outstanding. Holders of unvested shares of restricted stock are eligible to receive non-forfeitable dividends. As such, unvested shares of restricted stock are considered participating securities and therefore are included in the computation of basic net income per common share using the two-class method. Upon vesting, restrictions on transfer expire on each share of restricted stock, and each such share represents one unrestricted share of common stock. Because the Company’s 6.900% Series C Fixed-to-Floating Rate Cumulative Redeemable Preferred Stock (the “Series C Preferred Stock”) is redeemable at the Company’s option for cash only and convertible into shares of common stock only upon a change of control of the Company (and subject to other circumstances) as described in Article IIIC of the Company’s Articles of Amendment to the Restated Articles of Incorporation (the “Restated Articles of Incorporation, as amended”), the effect of those shares and their related dividends were excluded from the calculation of diluted net income per common share for the periods presented.
Cash and Cash Equivalents [Policy Text Block]	Cash Cash includes unrestricted demand deposits at highly rated financial institutions. The Company’s cash balances fluctuate throughout the year and may exceed Federal Deposit Insurance Company insured limits from time to time. Although the Company bears risk to amounts in excess of those insured by the FDIC, it does not anticipate any losses as a result due to the financial position and creditworthiness of the depository institutions in which those deposits are held.
Restricted Cash [Policy Text Block]	Cash Collateral Posted To/By Counterparties Cash collateral posted to/by counterparties represents amounts pledged/received to cover initial and variation margin related to the Company’s financing and derivative instruments. The following table provides a reconciliation of cash and cash posted to counterparties reported on the Company's consolidated balance sheet as of the period indicated that sum to the total of the same such amounts shown on the Company’s consolidated statement of cash flows for the three months ended March 31, 2021: March 31, 2021 Cash $ 328,936 Cash collateral posted to counterparties 49,180 Total cash and cash posted to counterparties shown on consolidated statement of cash flows $ 378,116
Mortgage-Back Securities, Policy	Mortgage-Backed Securities The Company’s MBS are recorded at fair value on the Company’s consolidated balance sheet. MBS purchased prior to January 1, 2021 are designated as available for sale (“AFS”) with changes in fair value reported in other comprehensive income (“OCI”) as an unrealized gain (loss) until the investment is sold or matures. Upon the sale of an AFS security, any unrealized gain or loss is reclassified out of accumulated other comprehensive income (“AOCI”) into net income as a realized “gain (loss) on sale of investments, net” using the specific identification method. Effective January 1, 2021, the Company elected the fair value option for all MBS purchased on or after that date with changes in fair value reported in net income as “gain (loss) on investments, net”. Management is electing the fair value option so that GAAP net income will reflect the changes in fair value for its future purchases of MBS in a manner consistent with the presentation and timing of the changes in fair value of its derivative instruments. Electing the fair value option is increasing as an industry trend for mortgage REITs who have not elected cash flow hedge accounting. “Gain (loss) on investments, net”, which was titled “fair value adjustments, net” in prior reporting periods, also includes changes in fair value for mortgage loans held for investment for which the Company elected the fair value option effective January 1, 2020. Interest Income, Premium Amortization, and Discount Accretion. Interest income on MBS is accrued based on the outstanding principal balance (or notional balance in the case of interest-only, or “IO” securities) and their contractual terms. Premiums or discounts associated with the purchase of Agency MBS as well as any non-Agency MBS are amortized or accreted into interest income over the projected life of such securities using the effective yield method, and adjustments to premium amortization and discount accretion are made for actual cash payments. The Company’s projections of future cash payments are based on input and analysis received from external sources and internal models and include assumptions about the amount and timing of loan prepayment rates, fluctuations in interest rates, credit losses, and other factors. On at least a quarterly basis, the Company reviews and makes any necessary adjustments to its cash flow projections and updates the yield recognized on these assets. The Company does not currently hold any non-Agency MBS that were purchased at a discount with credit ratings of less than ‘AA’ or not rated by any of the nationally recognized credit rating agencies at the time of purchase. Determination of MBS Fair Value. The Company estimates the fair value of the majority of its MBS based upon prices obtained from pricing services and broker quotes. The remainder of the Company’s MBS are valued by discounting the estimated future cash flows derived from cash flow models that utilize information such as the security’s coupon rate, estimated prepayment speeds, expected weighted average life, collateral composition, estimated future interest rates, expected losses, and credit enhancements as well as certain other relevant information. Please refer to Note 5 for further discussion of MBS fair value measurements. Allowance for Credit Losses. On at least a quarterly basis, the Company evaluates any MBS designated as AFS with a fair value less than its amortized cost for credit losses. If the difference between the present value of cash flows expected to be collected on the MBS is less than its amortized cost, the difference is recorded as an allowance for credit loss through net income up to and not exceeding the amount that the amortized cost exceeds current fair value. Subsequent changes in credit loss estimates are recognized in earnings in the period in which they occur. Because the majority of the Company’s investments are higher credit quality and most are guaranteed by a GSE, the Company is not likely to have an allowance for credit losses related to its MBS recorded on its consolidated balance sheet.
Repurchase Agreements [Policy Text Block]	Repurchase Agreements The Company’s repurchase agreements, which are used to finance its purchases of MBS, are accounted for as secured borrowings under which the Company pledges its securities as collateral to secure a loan, which is equal in value to a specified percentage of the estimated fair value of the pledged collateral. The Company retains beneficial ownership of the pledged collateral, which is disclosed parenthetically on the Company’s consolidated balance sheets. At the maturity of a repurchase agreement, the Company is required to repay the loan and concurrently receives back its pledged collateral from the lender or, with the consent of the lender, the Company may renew the agreement at the then prevailing financing rate. A repurchase agreement lender may require the Company to pledge additional collateral in the event of a decline in the fair value of the collateral pledged. Repurchase agreement financing is recourse to the Company and the assets pledged. Most of the Company’s repurchase agreements are based on the September 1996 version of the Bond Market Association Master Repurchase Agreement, which generally provides that the lender, as buyer, is responsible for obtaining collateral valuations from a generally recognized source agreed to by both the Company and the lender, or, in an instance when such source is not available, the value determination is made by the lender.
Derivative Instruments [Policy Text Block]	Derivative Instruments As of March 31, 2021, the Company’s derivative instruments include U.S. Treasury futures, options on U.S. Treasury futures, options on interest rate swaps (“swaptions”) and TBA securities, which are forward contracts for the purchase or sale of Agency RMBS on a non-specified pool basis. Derivative instruments are reported at their fair value on the Company’s consolidated balance sheet as derivative assets if in a gain position or as derivative liabilities if in a loss position, at the end of the period reported. All periodic interest benefits/costs and changes in fair value of derivative instruments, including gains and losses realized upon termination, maturity, or settlement are recorded in “gain (loss) on derivative instruments, net” on the Company’s consolidated statement of comprehensive income (loss). Cash receipts and payments related to derivative instruments are classified in the investing activities section of the consolidated statements of cash flows in accordance with the underlying nature or purpose of the derivative transactions. The Company currently has short positions in U.S. Treasury futures contracts, which are valued based on exchange pricing with daily margin settlements. The Company realizes gains or losses on these contracts upon expiration at an amount equal to the difference between the current fair value of the underlying asset and the contractual price of the futures contract. Daily margin exchanges for the Company’s U.S. Treasury futures are not considered legal settlement of the instrument. The Company’s options on U.S. Treasury futures provide the Company the right, but not an obligation, to buy U.S. Treasury futures at a predetermined notional amount and stated term in the future. Options on U.S. Treasury futures are valued based on exchange pricing without daily exchanges of margin amounts. The Company records the premium paid for the option contract as a derivative asset on its consolidated balance sheet and adjusts the balance for changes in fair value through “gain (loss) on derivative instruments” until the option is exercised or the contract expires. The Company may also purchase swaptions and defer the premium payment until the effective date. The premium payable and underlying swaption are accounted for as a single unit of account. A TBA security is a forward contract (“TBA contract”) for the purchase (“long position”) or sale (“short position”) of a non-specified Agency MBS at a predetermined price with certain principal and interest terms and certain types of collateral, but the particular Agency securities to be delivered are not identified until shortly before the settlement date. The Company accounts for long and short positions in TBAs as derivative instruments because the Company cannot assert that it is probable at inception and throughout the term of an individual TBA transaction that its settlement will result in physical delivery of the underlying Agency RMBS or that the individual TBA transaction will not settle in the shortest time period possible. Please refer to Note 4 for additional information regarding the Company’s derivative instruments as well as Note 5 for information on how the fair value of these instruments is calculated.
Share-based Compensation [Policy Text Block]	Share-Based CompensationPursuant to the Company’s 2020 Stock and Incentive Plan (the “2020 Plan”), the Company may grant share-based compensation to eligible employees, non-employee directors or consultants or advisors to the Company, including restricted stock awards, stock options, stock appreciation rights, performance-based and service-based restricted stock units, and performance cash awards. Currently, the Company has shares of restricted stock issued and outstanding which are treated as equity awards and recorded at their fair value which is measured using the closing stock price on the date of the grant. The compensation cost is recognized over the vesting period with a corresponding credit to shareholders’ equity using the straight-line method. The Company does not estimate forfeiture rates, but adjusts for actual forfeitures in the periods in which they occur. The Company does not currently have any share-based compensation issued or outstanding other than restricted stock issued to its employees, officers, and directors.
Contingencies [Policy Text Block]	Contingencies In the normal course of business, there may be various lawsuits, claims, and other contingencies pending against the Company. On a quarterly basis, the Company evaluates whether to establish provisions for estimated losses from those matters. The Company recognizes a liability for a contingent loss when: (a) the underlying causal event has occurred prior to the balance sheet date; (b) it is probable that a loss has been incurred; and (c) there is a reasonable basis for estimating that loss. A liability is not recognized for a contingent loss when it is only possible or remotely possible that a loss has been incurred, however, possible contingent losses shall be disclosed. If the contingent loss (or an additional loss in excess of any accrual) is at least a reasonable possibility and material, then the Company discloses a reasonable estimate of the possible loss or range of loss, if such reasonable estimate can be made. If the Company cannot make a reasonable estimate of the possible material loss, or range of loss, then that fact is disclosed. As previously disclosed in the 2020 Form 10-K, the receiver (the “Receiver”) for one of the plaintiffs awarded damages in a judgment (the "DCI Judgment") against Dynex Commercial, Inc. ("DCI"), a subsidiary of a former affiliate of the Company, filed a separate claim in May 2018 against the Company seeking payment of the damages awarded in connection with the DCI Judgment, alleging that the Company breached a litigation cost sharing agreement, as amended (the "Agreement"), that was initially entered into by the Company and DCI in December 2000. On November 21, 2019, the U.S. District Court, Northern District of Texas ("Northern District Court") granted in part and denied in part summary judgment on the Receiver’s claim and the Company’s claim for offset and recoupment. The Northern District Court found that the Company breached the Agreement and therefore must pay damages to the Receiver. The Northern District Court simultaneously granted the Company’s motion for summary judgment finding that DCI also breached the Agreement and that the Company can recover amounts due to it from DCI under the Agreement. The Receiver subsequently filed a claim for damages with the Northern District Court of approximately $12,600, while the Company filed claims for damages ranging
New Accounting Pronouncements, Policy	Recently Issued Accounting Pronouncements The Company evaluates Accounting Standards Updates (“ASU”) issued by the Financial Accounting Standards Board (“FASB”) on at least a quarterly basis to evaluate applicability and significance of any impact on its financial condition and results of operations. There were no accounting pronouncements issued during the three months ended March 31, 2021 that are expected to have a material impact on the Company’s financial condition or results of operations.

Mortgage-Backed Securities (Tab

Mortgage-Backed Securities (Tables)	3 Months Ended
	Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Debt Securities, Available-for-sale [Table Text Block]	The following tables present the Company’s MBS by investment type as of the dates indicated: March 31, 2021 Agency RMBS Agency CMBS CMBS IO (1) Non-Agency Other Total MBS designated as AFS: Par value $ 1,651,864 $ 234,091 $ — $ 1,354 $ 1,887,309 Unamortized premium (discount) 55,118 2,975 352,655 (370) 410,378 Amortized cost 1,706,982 237,066 352,655 984 2,297,687 Gross unrealized gain 13,646 12,551 14,200 202 40,599 Gross unrealized loss (24,473) — (979) (43) (25,495) Fair value 1,696,155 249,617 365,876 1,143 2,312,791 MBS measured at fair value through net income: Par value $ 67,692 $ — $ — $ — $ 67,692 Unamortized premium (discount) 850 — — — 850 Amortized cost 68,542 — — — 68,542 Gross unrealized gain — — — — — Gross unrealized loss (960) — — — (960) Fair value 67,582 — — — 67,582 Total as of March 31, 2021 $ 1,763,737 $ 249,617 $ 365,876 $ 1,143 $ 2,380,373 (1) The notional balance for Agency CMBS IO and non-Agency CMBS IO was $11,097,619 and $9,209,025 respectively, as of March 31, 2021. December 31, 2020 Agency RMBS Agency CMBS CMBS IO (1) Non-Agency Other Total MBS designated as AFS: Par value $ 1,839,046 $ 235,801 $ — $ 1,499 $ 2,076,346 Unamortized premium (discount) 57,997 3,152 378,940 (440) 439,649 Amortized cost 1,897,043 238,953 378,940 1,059 2,515,995 Gross unrealized gain 49,348 19,597 12,081 267 81,293 Gross unrealized loss — — (982) (51) (1,033) Fair value 1,946,391 258,550 390,039 1,275 2,596,255 MBS measured at fair value through net income: Par value $ — $ — $ — $ — $ — Unamortized premium (discount) — — — — — Amortized cost — — — — — Gross unrealized gain — — — — — Gross unrealized loss — — — — — Fair value — — — — — Total as of December 31, 2020 $ 1,946,391 $ 258,550 $ 390,039 $ 1,275 $ 2,596,255 (1) The notional balance for the Agency CMBS IO and non-Agency CMBS IO was $11,277,908 and $9,319,520, respectively, as of December 31, 2020.
Schedule of Realized Gain (Loss) [Table Text Block]	The following table presents information regarding the "gain on sale of investments, net" on the Company’s consolidated statements of comprehensive income (loss) for the periods indicated: Three Months Ended March 31, 2021 2020 Proceeds Received Realized Gain Proceeds Received Realized Gain Agency RMBS-designated as AFS $ 74,829 $ 4,697 $ 1,817,350 $ 64,094 Agency CMBS-designated as AFS — — 173,684 20,689 $ 74,829 $ 4,697 $ 1,991,034 $ 84,783
Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value [Table Text Block]	The following table presents certain information for the AFS securities in an unrealized loss position as of the dates indicated: March 31, 2021 December 31, 2020 Fair Value Gross Unrealized Losses # of Securities Fair Value Gross Unrealized Losses # of Securities Continuous unrealized loss position for less than 12 months: Agency MBS $ 1,446,354 $ (25,019) 32 $ 19,266 $ (399) 19 Non-Agency MBS 5,221 (111) 5 33,417 (408) 23 Continuous unrealized loss position for 12 months or longer: Agency MBS $ 846 $ (224) 5 $ 749 $ (133) 2 Non-Agency MBS 5,029 (140) 8 2,156 (93) 5

Repurchase Agreements (Tables)

Repurchase Agreements (Tables)	3 Months Ended
	Mar. 31, 2021
Disclosure of Repurchase Agreements [Abstract]
Schedule of Underlying Assets of Repurchase Agreements when Amount of Repurchase Agreements Exceeds 10 Percent of Assets [Table Text Block]	The Company’s repurchase agreements outstanding as of March 31, 2021 and December 31, 2020 are summarized in the following tables: March 31, 2021 December 31, 2020 Collateral Type Balance Weighted Fair Value of Balance Weighted Fair Value of Agency RMBS $ 1,499,034 0.16 % $ 1,568,623 $ 1,874,176 0.23 % $ 1,973,608 Agency CMBS 234,228 0.16 % 246,936 237,649 0.23 % 255,741 Agency CMBS IO 191,882 0.78 % 228,854 209,393 0.90 % 243,042 Non-Agency CMBS IO 106,945 1.01 % 128,920 115,945 1.28 % 136,684 Total repurchase agreements $ 2,032,089 0.26 % $ 2,173,333 $ 2,437,163 0.34 % $ 2,609,075
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Table Text Block]	The following table provides information on the remaining term to maturity and original term to maturity for the Company’s repurchase agreements as of the dates indicated: March 31, 2021 December 31, 2020 Remaining Term to Maturity Balance Weighted WAVG Original Term to Maturity Balance Weighted WAVG Original Term to Maturity Less than 30 days $ 1,119,808 0.27 % 24 $ 1,416,608 0.37 % 53 30 to 90 days 753,223 0.28 % 42 845,394 0.31 % 35 91 to 180 days 159,058 0.17 % 14 175,161 0.22 % 13 Total $ 2,032,089 0.26 % 30 $ 2,437,163 0.34 % 44

Derivatives (Tables)

Derivatives (Tables)	3 Months Ended
	Mar. 31, 2021
Derivative [Line Items]
Derivative Instruments, Gain (Loss)	The table below provides detail of the Company’s “gain (loss) on derivative instruments, net” by type of derivative for the periods indicated: Three Months Ended March 31, Type of Derivative Instrument 2021 2020 Interest rate swaps $ — $ (182,181) Interest rate swaptions 57,763 (573) U.S. Treasury futures 95,647 (8,447) Options on U.S. Treasury futures 12,617 (10,727) TBA securities - long positions (58,226) 18,432 TBA securities - short positions — (12,071) Gain (loss) on derivative instruments, net $ 107,801 $ (195,567)
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The table below summarizes information about the carrying value by type of derivative instrument on the Company’s consolidated balance sheets as of the dates indicated: Type of Derivative Instrument Balance Sheet Location Purpose March 31, 2021 December 31, 2020 U.S. Treasury futures Derivative assets Economic hedging $ 72,723 $ — Options on U.S. Treasury futures Derivative assets Economic hedging 9,180 1,094 Interest rate swaptions Derivative assets Economic hedging 27,843 1,360 TBA securities Derivative assets Investing — 8,888 Total derivatives assets $ 109,746 $ 11,342 Interest rate swaptions Derivative liabilities Economic hedging $ — $ (107) U.S. Treasury futures Derivative liabilities Economic hedging — (1,527) TBA securities Derivative liabilities Investing (19,866) — Total derivatives liabilities $ (19,866) $ (1,634)
Schedule of Notional Amounts of Outstanding Derivative Positions	The tables below summarize changes in the Company’s derivative instruments for the three months ended March 31, 2021: Type of Derivative Instrument Beginning Additions Settlements, Ending Interest rate swaptions 1,250,000 — (750,000) 500,000 U.S. Treasury futures (825,000) (4,010,000) 1,855,000 (2,980,000) Options on U.S. Treasury futures 500,000 1,500,000 (1,750,000) 250,000 TBA securities 1,515,000 8,065,000 (6,780,000) 2,800,000
Offsetting Assets	Offsetting of Assets Gross Amount of Recognized Assets Gross Amount Offset in the Balance Sheet Net Amount of Assets Presented in the Balance Sheet Gross Amount Not Offset in the Balance Sheet (1) Net Amount Financial Instruments Received as Collateral Cash Received as Collateral March 31, 2021 U.S. Treasury futures $ 72,723 $ — $ 72,723 $ — $ (26,430) $ 46,293 Options on U.S. Treasury futures 9,180 — 9,180 — — 9,180 Interest rate swaptions 27,843 — 27,843 — (27,843) — Derivative assets $ 109,746 $ — $ 109,746 $ — $ (54,273) $ 55,473 December 31, 2020 Interest rate swaptions $ 1,360 $ — $ 1,360 $ (107) $ — $ 1,253 Options on U.S. Treasury futures 1,094 — 1,094 — — 1,094 TBA securities 8,888 — 8,888 — (7,681) 1,207 Derivative assets $ 11,342 $ — $ 11,342 $ (107) $ (7,681) $ 3,554
Offsetting Liabilities	Offsetting of Liabilities Gross Amount of Recognized Liabilities Gross Amount Offset in the Balance Sheet Net Amount of Liabilities Presented in the Balance Sheet Gross Amount Not Offset in the Balance Sheet (1) Net Amount Financial Instruments Posted as Collateral Cash Posted as Collateral March 31, 2021 TBA securities $ (19,866) — $ (19,866) $ — $ 19,866 $ — Derivative liabilities $ (19,866) $ — $ (19,866) $ — $ 19,866 $ — December 31, 2020 U.S. Treasury futures-short positions $ (1,527) — $ (1,527) $ — $ 1,527 $ — Interest rate swaptions (107) — (107) 107 — — Derivative liabilities $ (1,634) $ — $ (1,634) $ 107 $ 1,527 $ — (1) Amounts disclosed for collateral received by or posted to the same counterparty include cash and the fair value of MBS up to and not exceeding the net amount of the derivative asset or liability presented in the balance sheet. The fair value of the total collateral received by or posted to the same counterparty may exceed the amounts presented. Please refer to the consolidated balance sheets for the total fair value of financial instruments pledged as collateral for derivatives and repurchase agreements, which is shown parenthetically, and the total cash pledged or received as collateral which is disclosed in “cash collateral posted to/by counterparties.”

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Disclosures	FAIR VALUE OF FINANCIAL INSTRUMENTS Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value is based on the assumptions market participants would use when pricing an asset or liability and also considers all aspects of nonperformance risk, including the entity’s own credit standing, when measuring fair value of a liability. ASC Topic 820 established a valuation hierarchy of three levels as follows: • Level 1 – Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities as of the measurement date. • Level 2 – Inputs include quoted prices in active markets for similar assets or liabilities; quoted prices in inactive markets for identical or similar assets or liabilities; or inputs either directly observable or indirectly observable through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life. • Level 3 – Unobservable inputs are supported by little or no market activity. The unobservable inputs represent management’s best estimate of how market participants would price the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model. The following table presents the Company’s financial instruments that are measured at fair value on the Company’s consolidated balance sheet by their valuation hierarchy levels as of the dates indicated: March 31, 2021 December 31, 2020 Fair Value Level 1 Level 2 Level 3 Fair Value Level 1 Level 2 Level 3 Assets carried at fair value: MBS $ 2,380,373 $ — $ 2,379,230 $ 1,143 $ 2,596,255 $ — $ 2,594,980 $ 1,275 Mortgage loans held for investment 5,749 — — 5,749 6,264 — — 6,264 Derivative assets: U.S. Treasury futures $ 72,723 72,723 — — — — — — Options on U.S. Treasury futures 9,180 9,180 — — 1,094 1,094 — — Interest rate swaptions 27,843 — 27,843 — 1,360 — 1,360 — TBA securities-long positions — — — — 8,888 — 8,888 — Total assets carried at fair value $ 2,495,868 $ 81,903 $ 2,407,073 $ 6,892 $ 2,613,861 $ 1,094 $ 2,605,228 $ 7,539 Liabilities carried at fair value: U.S. Treasury futures $ — $ — $ — $ — $ 1,527 $ 1,527 $ — $ — Interest rate swaptions — — — — 107 — 107 — TBA securities-long positions 19,866 — 19,866 — — — — — Total liabilities carried at fair value $ 19,866 $ — $ 19,866 $ — $ 1,634 $ 1,527 $ 107 $ — The fair value measurements for the Company's MBS are considered Level 2 when there are substantially similar securities actively trading or for which there has been recent trading activity in their respective markets and are based on prices received from pricing services and quotes from brokers. In valuing a security, the pricing service uses either a market approach, which uses observable prices and other relevant information that is generated by market transactions of identical or similar securities, or an income approach, which uses valuation techniques to convert future amounts to a single, discounted present value amount. The Company reviews the prices it receives from its pricing sources as well as the assumptions and inputs utilized by its pricing sources for reasonableness. Examples of these observable inputs and assumptions include market interest rates, credit spreads, and projected prepayment speeds, among other things. The Company owns other non-Agency MBS and mortgage loans that are considered Level 3 assets because there has been no recent trading activity of similar instruments upon which their fair value can be measured. The fair value for these Level 3 assets is measured by discounting the estimated future cash flows derived from cash flow models using significant inputs which are determined by the Company when market observable inputs are not available. Information utilized in those pricing models include the security’s credit rating, coupon rate, estimated prepayment speeds, expected weighted average life, collateral composition, estimated future interest rates, expected credit losses, and credit enhancement as well as certain other relevant information. The Company used a constant prepayment rate assumption of 10%, default rate of 2%, loss severity of 20%, and a discount rate of 7.0% in measuring the fair value of its Level 3 assets as of March 31, 2021. Significant changes in any of these inputs in isolation may result in a significantly different fair value measurement. Level 3 assets are generally most sensitive to the default rate and severity assumptions. The activity of the Company’s Level 3 assets during the three months ended March 31, 2021 is presented in the following table: Three Months Ended March 31, 2021 Other Non-Agency MBS Mortgage Loans Balance as of beginning of period $ 1,275 $ 6,264 Change in fair value (1) (57) (22) Principal payments (145) (488) Accretion (amortization) 70 (5) Balance as of end of period $ 1,143 $ 5,749 (1) Change in fair value for mortgage loans is recorded as unrealized gain (loss) in “gain (loss) on investments, net” in net income and change in fair value for other non-Agency MBS is recorded as unrealized gain (loss) in “other comprehensive income”. U.S. Treasury futures and options on U.S. Treasury futures are valued based on closing exchange prices on these contracts and are classified accordingly as Level 1 measurements. The fair value of interest rate swaptions is based on the fair value of the underlying interest rate swap and time remaining until its expiration and is carried on the balance sheet net of any deferred premium to be paid upon expiration. The fair value of TBA securities is estimated using methods similar those used to fair value the Company’s Level 2 MBS.
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The following table presents the Company’s financial instruments that are measured at fair value on the Company’s consolidated balance sheet by their valuation hierarchy levels as of the dates indicated: March 31, 2021 December 31, 2020 Fair Value Level 1 Level 2 Level 3 Fair Value Level 1 Level 2 Level 3 Assets carried at fair value: MBS $ 2,380,373 $ — $ 2,379,230 $ 1,143 $ 2,596,255 $ — $ 2,594,980 $ 1,275 Mortgage loans held for investment 5,749 — — 5,749 6,264 — — 6,264 Derivative assets: U.S. Treasury futures $ 72,723 72,723 — — — — — — Options on U.S. Treasury futures 9,180 9,180 — — 1,094 1,094 — — Interest rate swaptions 27,843 — 27,843 — 1,360 — 1,360 — TBA securities-long positions — — — — 8,888 — 8,888 — Total assets carried at fair value $ 2,495,868 $ 81,903 $ 2,407,073 $ 6,892 $ 2,613,861 $ 1,094 $ 2,605,228 $ 7,539 Liabilities carried at fair value: U.S. Treasury futures $ — $ — $ — $ — $ 1,527 $ 1,527 $ — $ — Interest rate swaptions — — — — 107 — 107 — TBA securities-long positions 19,866 — 19,866 — — — — — Total liabilities carried at fair value $ 19,866 $ — $ 19,866 $ — $ 1,634 $ 1,527 $ 107 $ —
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The activity of the Company’s Level 3 assets during the three months ended March 31, 2021 is presented in the following table: Three Months Ended March 31, 2021 Other Non-Agency MBS Mortgage Loans Balance as of beginning of period $ 1,275 $ 6,264 Change in fair value (1) (57) (22) Principal payments (145) (488) Accretion (amortization) 70 (5) Balance as of end of period $ 1,143 $ 5,749

Shareholders' Equity and Shar_2

Shareholders' Equity and Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2021
Equity [Abstract]
Dividends Declared	Common Stock. The following table summarizes information regarding monthly dividend declarations on the Company’s common stock during the three months ended March 31, 2021: Three Months Ended March 31, 2021 Declaration Date Amount Declared Record Date Payment Date January 13, 2021 $ 0.13 January 25, 2021 February 1, 2021 February 11, 2021 0.13 February 22, 2021 March 1, 2021 March 11, 2021 0.13 March 22, 2021 April 1, 2021
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity	The following table presents a rollforward of the restricted stock activity for the periods indicated: Three Months Ended March 31, 2021 March 31, 2020 Shares Weighted Average Grant Date Fair Value Per Share Shares Weighted Average Grant Date Fair Value Per Share Restricted stock outstanding as of beginning of period 281,761 $ 14.74 119,213 $ 18.56 Granted 16,722 19.03 67,511 17.10 Vested (59,024) 18.02 (48,569) 19.02 Restricted stock outstanding as of end of period 239,459 $ 14.23 138,155 $ 17.69

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Cash	$ 328,936	$ 295,602
Cash collateral posted to counterparties	49,180	14,758
Total cash and cash posted to counterparties shown on consolidated statement of cash flows	378,116	$ 310,360	$ 115,800	$ 136,230
Prior Period Reclassification Adjustment	$ 7,681

Commitment and Contingencies (D

Commitment and Contingencies (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Commitments and Contingencies Disclosure [Abstract]
Loss Contingency, Damages Sought, Value	$ 12,600
Loss Contingency, Inestimable Loss	After consultation with litigation counsel, the Company believes, based upon information currently available and its evaluation of Virginia law, that the likelihood of loss is not probable, and given the range of potential claims for damages by the Company to offset the Receiver's claims, the amount of possible loss cannot be reasonably estimated, and therefore, no contingent liability has been recorded.

Mortgage-Backed Securities (Det

Mortgage-Backed Securities (Details)	3 Months Ended
	Mar. 31, 2021USD ($)		Mar. 31, 2020USD ($)	Dec. 31, 2020USD ($)
Investments [Line Items]
Debt Securities, Trading, Amortized Cost	$ 68,542,000
Debt Securities, Trading, Unrealized Gain	0
Debt Securities, Trading, Unrealized Loss	(960,000)
Debt Securities, Trading	67,582,000
Debt Securities, Trading and Available-for-sale	2,380,373,000
Proceeds from Sale of Available-for-sale Securities	74,829,000		$ 1,991,034,000
Debt Securities, Available-for-sale, Realized Gain (Loss)	4,697,000		84,783,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year				2
Debt Securities, Available-for-sale, Allowance for Credit Loss	0
Par value of available for sale debt security	1,887,309,000			$ 2,076,346,000
Debt Securities, Available-for-sale, Amortized Cost	2,297,687,000			2,515,995,000
Debt Securities, Available-for-sale	2,312,791,000			2,596,255,000
Par Value of Debt Security, Fair Value Option Elected	67,692,000
Investments, Unamortized Premium (Discount)	410,378,000			439,649,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	40,599,000			81,293,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(25,495,000)			(1,033,000)
Fair Value Option
Investments [Line Items]
Investments, Unamortized Premium (Discount)	850,000
Residential Mortgage Backed Securities
Investments [Line Items]
Par value of available for sale debt security				1,839,046,000
Debt Securities, Available-for-sale, Amortized Cost				1,897,043,000
Debt Securities, Available-for-sale				1,946,391,000
Investments, Unamortized Premium (Discount)				57,997,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax				49,348,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax				0
Residential Mortgage Backed Securities | Agency MBS
Investments [Line Items]
Debt Securities, Trading, Amortized Cost	68,542,000
Debt Securities, Trading, Unrealized Gain	0
Debt Securities, Trading, Unrealized Loss	(960,000)
Debt Securities, Trading	67,582,000
Debt Securities, Trading and Available-for-sale	1,763,737,000
Proceeds from Sale of Available-for-sale Securities	74,829,000		1,817,350,000
Debt Securities, Available-for-sale, Realized Gain	4,697,000
Debt Securities, Available-for-sale, Realized Loss			64,094,000
Par value of available for sale debt security	1,651,864,000
Debt Securities, Available-for-sale, Amortized Cost	1,706,982,000
Debt Securities, Available-for-sale	1,696,155,000			1,946,391,000
Par Value of Debt Security, Fair Value Option Elected	67,692,000
Investments, Unamortized Premium (Discount)	55,118,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	13,646,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(24,473,000)
Residential Mortgage Backed Securities | Agency MBS | Fair Value Option
Investments [Line Items]
Investments, Unamortized Premium (Discount)	850,000
Commercial Mortgage Backed Securities
Investments [Line Items]
Proceeds from Sale of Available-for-sale Securities	0
Debt Securities, Available-for-sale, Realized Loss	0
Debt Securities, Available-for-sale, Amortized Cost				238,953,000
Debt Securities, Available-for-sale				258,550,000
Investments, Unamortized Premium (Discount)				3,152,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax				19,597,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax				0
Commercial Mortgage Backed Securities | Agency MBS
Investments [Line Items]
Debt Securities, Trading and Available-for-sale	249,617,000
Proceeds from Sale of Available-for-sale Securities			173,684,000
Debt Securities, Available-for-sale, Realized Loss			$ 20,689,000
Par value of available for sale debt security	234,091,000			235,801,000
Debt Securities, Available-for-sale, Amortized Cost	237,066,000
Debt Securities, Available-for-sale	249,617,000			258,550,000
Investments, Unamortized Premium (Discount)	2,975,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	12,551,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	0
Interest-Only-Strip
Investments [Line Items]
Debt Securities, Trading and Available-for-sale	365,876,000
Par value of available for sale debt security	0	[1]		0
Debt Securities, Available-for-sale, Amortized Cost	352,655,000			378,940,000
Debt Securities, Available-for-sale	365,876,000			390,039,000
Investments, Unamortized Premium (Discount)	352,655,000			378,940,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	14,200,000			12,081,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(979,000)			(982,000)
Non-Agency MBS
Investments [Line Items]
Notional balance for interest only securities	9,209,025,000			9,319,520,000
Debt Securities, Trading and Available-for-sale	1,143,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	5,221,000			33,417,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 111,000			$ 408,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	5			23
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 5,029,000			$ 2,156,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 140,000			$ 93,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	8			5
Par value of available for sale debt security	$ 1,354,000			$ 1,499,000
Debt Securities, Available-for-sale, Amortized Cost	984,000			1,059,000
Debt Securities, Available-for-sale	1,143,000			1,275,000
Investments, Unamortized Premium (Discount)	(370,000)			(440,000)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	202,000			267,000
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(43,000)			(51,000)
Agency MBS
Investments [Line Items]
Notional balance for interest only securities	11,097,619,000			11,277,908,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,446,354,000			19,266,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	$ 25,019,000			$ 399,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	32			19
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	$ 846,000			$ 749,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	$ 224,000			$ 133,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	5
[1]	The notional balance for Agency CMBS IO and non-Agency CMBS IO was $11,097,619 and $9,209,025 respectively, as of March 31, 2021. December 31, 2020 Agency RMBS Agency CMBS CMBS IO (1) Non-Agency Other Total MBS designated as AFS: Par value $ 1,839,046 $ 235,801 $ — $ 1,499 $ 2,076,346 Unamortized premium (discount) 57,997 3,152 378,940 (440) 439,649 Amortized cost 1,897,043 238,953 378,940 1,059 2,515,995 Gross unrealized gain 49,348 19,597 12,081 267 81,293 Gross unrealized loss — — (982) (51) (1,033) Fair value 1,946,391 258,550 390,039 1,275 2,596,255 MBS measured at fair value through net income: Par value $ — $ — $ — $ — $ — Unamortized premium (discount) — — — — — Amortized cost — — — — — Gross unrealized gain — — — — — Gross unrealized loss — — — — — Fair value — — — — — Total as of December 31, 2020 $ 1,946,391 $ 258,550 $ 390,039 $ 1,275 $ 2,596,255

Repurchase Agreements (Details)

Repurchase Agreements (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 2,032,089	$ 2,437,163
Weighted Average Rate	0.26%	0.34%
Fair Value of Collateral Pledged	$ 2,173,333	$ 2,609,075
Payable for unsettled securities		5
Receivable for sales pending settlement	5,067	150,432
Repurchase agreement amount for which securities sold but unsettled as of reporting date are pledged as collateral.		140,612
Amortized cost of securities sold but unsettled		141,215
Residential Mortgage Backed Securities | Agency MBS
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 1,499,034	$ 1,874,176
Weighted Average Rate	0.16%	0.23%
Fair Value of Collateral Pledged	$ 1,568,623	$ 1,973,608
Commercial Mortgage Backed Securities | Agency MBS
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 234,228	$ 237,649
Weighted Average Rate	0.16%	0.23%
Fair Value of Collateral Pledged	$ 246,936	$ 255,741
Interest-Only-Strip | Agency MBS
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 191,882	$ 209,393
Weighted Average Rate	0.78%	0.90%
Fair Value of Collateral Pledged	$ 228,854	$ 243,042
Interest-Only-Strip | Non-Agency MBS
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 106,945	$ 115,945
Weighted Average Rate	1.01%	1.28%
Fair Value of Collateral Pledged	$ 128,920	$ 136,684

Repurchase Agreements Remaining

Repurchase Agreements Remaining Term to Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 2,032,089	$ 2,437,163
Assets Sold under Agreements to Repurchase, Interest Rate	0.26%	0.34%
WAVG Original Term to Maturity	30	44
Less than 30 days
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 1,119,808	$ 1,416,608
Assets Sold under Agreements to Repurchase, Interest Rate	0.27%	0.37%
WAVG Original Term to Maturity	24	53
30 to 90 days
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 753,223	$ 845,394
Assets Sold under Agreements to Repurchase, Interest Rate	0.28%	0.31%
WAVG Original Term to Maturity	42	35
Maturity Greater than 90 Days
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Assets Sold under Agreements to Repurchase, Repurchase Liability	$ 159,058	$ 175,161
Assets Sold under Agreements to Repurchase, Interest Rate	0.17%	0.22%
WAVG Original Term to Maturity	14	13

Repurchase Agreements Counterpa

Repurchase Agreements Counterparty Information (Details) $ in Thousands	Mar. 31, 2021USD ($)Agreements
Disclosure of Repurchase Agreements [Abstract]
Number of Counterparties with Borrowings Outstanding | Agreements	20
Line of Credit Facility, Maximum Borrowing Capacity	$ 250,000
Long-term Line of Credit	$ 114,251
Line of Credit Facility, Interest Rate at Period End	0.97%

Repurchase Agreements Offsettin

Repurchase Agreements Offsetting (Details) - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020
Offsetting Liabilities [Line Items]
Gross Amount of Recognized Liabilities			$ 2,437,163
Gross Amount Offset in the Balance Sheet		$ 0	0
Net Amount of Liabilities Presented in the Balance Sheet		2,032,089	2,437,163
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	[1]	(2,032,089)	(2,437,163)
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash		0	0
Securities Sold under Agreements to Repurchase, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election		$ 0	$ 0
[1]	Amounts disclosed for collateral received by or posted to the same counterparty include cash and the fair value of MBS up to and not exceeding the net amount of the repurchase agreement liability presented in the balance sheet. The fair value of the total collateral received by or posted to the same counterparty may exceed the amounts presented.

Derivatives (Details)

Derivatives (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		$ 107,801	$ (195,567)
Derivative Liability, Fair Value, Gross Liability		19,866		$ 1,634
Derivative assets, fair value		109,746		11,342
Derivative liabilities, fair value		(19,866)		(1,634)
Interest rate swaps
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Loss		0	(182,181)
Interest rate swaption
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain		57,763
Derivative Instruments Not Designated as Hedging Instruments, Loss			(573)
Derivative instrument, cost basis		$ 6,688		13,000
Derivative Liability, Fair Value, Gross Liability				$ 107
Derivative, Average Fixed Interest Rate		1.16%		1.07%
Derivative Asset, Notional Amount		$ 500,000		$ 1,250,000
Derivative assets, fair value		27,843		1,253
U.S. Treasury futures
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain		95,647
Derivative Instruments Not Designated as Hedging Instruments, Loss			(8,447)
Options on U.S. Treasury futures
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain		12,617
Derivative Instruments Not Designated as Hedging Instruments, Loss			(10,727)
Long position | TBA securities
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain			18,432
Derivative Instruments Not Designated as Hedging Instruments, Loss		(58,226)
Derivative Liability, Fair Value, Gross Liability		(19,866)
Short position | U.S. Treasury futures
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability				1,527
Short position | TBA securities
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Loss		0	$ (12,071)
Not Designated as Hedging Instrument, Economic Hedge | Interest rate swaption
Derivative [Line Items]
Derivative Asset, Notional Amount		500,000		1,250,000
Derivative assets, fair value		27,843		1,360
Derivative liabilities, fair value				(107)
Not Designated as Hedging Instrument, Economic Hedge | Interest rate swaption | 6 months or less
Derivative [Line Items]
Derivative instrument, cost basis		$ 2,963		$ 6,312
Derivative, Average Fixed Interest Rate		1.12%		1.02%
Derivative Asset, Notional Amount		$ 250,000		$ 750,000
Derivative assets, fair value		14,208		1,161
Not Designated as Hedging Instrument, Economic Hedge | Interest rate swaption | 6-9 months
Derivative [Line Items]
Derivative instrument, cost basis		$ 3,725		$ 6,688
Derivative, Average Fixed Interest Rate		1.19%		1.16%
Derivative Asset, Notional Amount		$ 250,000		$ 500,000
Derivative assets, fair value		13,635		92
Not Designated as Hedging Instrument, Economic Hedge | Options on U.S. Treasury futures
Derivative [Line Items]
Derivative Asset, Notional Amount		250,000		500,000
Derivative assets, fair value		$ 9,180		1,094
Derivative, Average Remaining Maturity	1 month	2 months
Not Designated as Hedging Instrument, Economic Hedge | Short position | U.S. Treasury futures
Derivative [Line Items]
Derivative Liability, Notional Amount		$ 2,980,000		825,000
Derivative assets, fair value		72,723
Derivative liabilities, fair value		$ 0		$ (1,527)
Derivative, Average Remaining Maturity		3 months		2 months
Not Designated as Hedging Instrument, Trading | Long position | TBA securities
Derivative [Line Items]
Derivative Asset, Notional Amount		$ 2,800,000		$ 1,515,000
Derivative assets, fair value				$ 8,888
Derivative liabilities, fair value		$ (19,866)

Derivatives TBA securities (Det

Derivatives TBA securities (Details) - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value		$ 109,746	$ 11,342
Long position | Not Designated as Hedging Instrument, Trading | TBA securities
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value			8,888
Cost Basis,TBA	[1]	(2,845,803)	(1,564,061)
Market value, TBA	[2]	(2,825,937)	(1,572,949)
Net carrying value, TBA	[3]	$ 19,866	$ (8,888)
[1]	Implied cost basis represents the forward price to be paid for the underlying Agency MBS as of the date indicated.
[2]	Implied market value represents the estimated fair value of the underlying Agency MBS as of the date indicated
[3]	Net carrying value is the amount included on the consolidated balance sheets within “derivative assets (liabilities)” and represents the difference between the implied market value and the implied cost basis of the TBA security as of the date indicated.

Derivatives Volume of Activity

Derivatives Volume of Activity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Interest rate swaption
Derivative [Line Items]
Derivative Asset, Notional Amount	$ 1,250,000
Derivative Asset, Notional Amount	500,000
Not Designated as Hedging Instrument, Economic Hedge | Interest rate swaption
Derivative [Line Items]
Derivative Asset, Notional Amount	1,250,000
Notional Amount of Derivative Instruments Added	0
Notional Amount of Derivative Instruments Maturing, Settled, Terminated, or Paired-Off	750,000
Derivative Asset, Notional Amount	500,000
Not Designated as Hedging Instrument, Economic Hedge | U.S. Treasury futures | Short position
Derivative [Line Items]
Derivative Liability, Notional Amount	825,000
Notional Amount of Derivative Instruments Added	(4,010,000)
Notional Amount of Derivative Instruments Maturing, Settled, Terminated, or Paired-Off	1,855,000
Derivative Liability, Notional Amount	2,980,000
Not Designated as Hedging Instrument, Economic Hedge | Options on U.S. Treasury futures
Derivative [Line Items]
Derivative Asset, Notional Amount	500,000
Notional Amount of Derivative Instruments Added	(1,500,000)
Notional Amount of Derivative Instruments Maturing, Settled, Terminated, or Paired-Off	1,750,000
Derivative Asset, Notional Amount	250,000
Not Designated as Hedging Instrument, Trading | TBA securities | Long position
Derivative [Line Items]
Derivative Asset, Notional Amount	1,515,000
Notional Amount of Derivative Instruments Added	(8,065,000)
Notional Amount of Derivative Instruments Maturing, Settled, Terminated, or Paired-Off	6,780,000
Derivative Asset, Notional Amount	$ 2,800,000

Derivatives Offsetting Assets (

Derivatives Offsetting Assets (Details) - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 109,746	$ 11,342
Derivative Asset, Fair Value, Gross Liability		0	0
Derivative assets		109,746	11,342
Derivative, Collateral, Obligation to Return Securities		0	(107)	[1]
Cash collateral posted by counterparties		54,273	7,681
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election		55,473	3,554
Options on U.S. Treasury futures
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset		9,180	1,094
Derivative Asset, Fair Value, Gross Liability		0	0
Derivative assets		9,180	1,094
Derivative, Collateral, Obligation to Return Securities		0	0
Cash collateral posted by counterparties		0	0
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election		9,180	1,094
Interest rate swaption
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset		27,843	1,360
Derivative Asset, Fair Value, Gross Liability		0	0
Derivative assets		27,843	1,360
Derivative, Collateral, Obligation to Return Securities		0	(107)
Cash collateral posted by counterparties		27,843	0
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election		0	1,253
Long position | TBA securities
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset			8,888
Derivative Asset, Fair Value, Gross Liability			0
Derivative assets			8,888
Derivative, Collateral, Obligation to Return Securities	[1]		0
Cash collateral posted by counterparties			7,681
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election			$ 1,207
Short position | U.S. Treasury futures
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset		72,723
Derivative Asset, Fair Value, Gross Liability		0
Derivative assets		72,723
Derivative, Collateral, Obligation to Return Securities		0
Cash collateral posted by counterparties		26,430
Derivative Asset, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election		$ 46,293
[1]	Amounts disclosed for collateral received by or posted to the same counterparty include cash and the fair value of MBS up to and not exceeding the net amount of the derivative asset or liability presented in the balance sheet. The fair value of the total collateral received by or posted to the same counterparty may exceed the amounts presented. Please refer to the consolidated balance sheets for the total fair value of financial instruments pledged as collateral for derivatives and repurchase agreements, which is shown parenthetically, and the total cash pledged or received as collateral which is disclosed in “cash collateral posted to/by counterparties.”

Derivatives Offsetting Liabilit

Derivatives Offsetting Liabilities (Details) - USD ($) $ in Thousands		Mar. 31, 2021		Dec. 31, 2020
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		$ (19,866)		$ (1,634)
Derivative Liability, Fair Value, Gross Asset		0		0
Derivative liabilities		19,866		1,634
Derivative, Collateral, Right to Reclaim Securities		0		107	[1]
Derivative, Collateral, Right to Reclaim Cash		19,866	[1]	1,527
Derivative Liability, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election		0		0
Interest rate swaption
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability				(107)
Derivative Liability, Fair Value, Gross Asset				0
Derivative liabilities				107
Derivative, Collateral, Right to Reclaim Securities	[1]			107
Derivative, Collateral, Right to Reclaim Cash				0
Derivative Liability, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election				0
Short position | U.S. Treasury futures
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability				(1,527)
Derivative Liability, Fair Value, Gross Asset				0
Derivative liabilities				1,527
Derivative, Collateral, Right to Reclaim Securities				0
Derivative, Collateral, Right to Reclaim Cash				1,527
Derivative Liability, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election				$ 0
Long position | TBA securities
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		19,866
Derivative Liability, Fair Value, Gross Asset		0
Derivative liabilities		(19,866)
Derivative, Collateral, Right to Reclaim Securities		0
Derivative, Collateral, Right to Reclaim Cash	[1]	19,866
Derivative Liability, Fair Value, Offset Against Collateral, Net of Not Subject to Master Netting Arrangement, Policy Election		$ 0
[1]	Amounts disclosed for collateral received by or posted to the same counterparty include cash and the fair value of MBS up to and not exceeding the net amount of the derivative asset or liability presented in the balance sheet. The fair value of the total collateral received by or posted to the same counterparty may exceed the amounts presented. Please refer to the consolidated balance sheets for the total fair value of financial instruments pledged as collateral for derivatives and repurchase agreements, which is shown parenthetically, and the total cash pledged or received as collateral which is disclosed in “cash collateral posted to/by counterparties.”

Fair Value of Financial Instr_3

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	$ 109,746	$ 11,342
Derivative liabilities	19,866	1,634
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	2,380,373	2,596,255
Assets, Fair Value Disclosure	2,495,868	2,613,861
Financial Liabilities Fair Value Disclosure	19,866	1,634
Mortgage loans held for investment, at fair value	5,749	6,264
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	0	0
Assets, Fair Value Disclosure	81,903	1,094
Financial Liabilities Fair Value Disclosure	0	1,527
Mortgage loans held for investment, at fair value	0	0
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	2,379,230	2,594,980
Assets, Fair Value Disclosure	2,407,073	2,605,228
Financial Liabilities Fair Value Disclosure	19,866	107
Mortgage loans held for investment, at fair value	0	0
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	1,143	1,275
Assets, Fair Value Disclosure	6,892	7,539
Financial Liabilities Fair Value Disclosure	0	0
Mortgage loans held for investment, at fair value	5,749	6,264
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	9,180	1,094
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	9,180	1,094
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Fair Value, Measurements, Recurring | Options on U.S. Treasury futures | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Fair Value, Measurements, Recurring | Interest rate swaption
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	27,843	1,360
Derivative liabilities		107
Fair Value, Measurements, Recurring | Interest rate swaption | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liabilities		0
Fair Value, Measurements, Recurring | Interest rate swaption | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	27,843	1,360
Derivative liabilities		107
Fair Value, Measurements, Recurring | Interest rate swaption | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0	0
Derivative liabilities		0
Fair Value, Measurements, Recurring | TBA securities | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		8,888
Derivative liabilities	19,866
Fair Value, Measurements, Recurring | TBA securities | Level 1 | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		0
Derivative liabilities	0
Fair Value, Measurements, Recurring | TBA securities | Level 2 | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		8,888
Derivative liabilities	19,866
Fair Value, Measurements, Recurring | TBA securities | Level 3 | Long position
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset		0
Derivative liabilities	0
Fair Value, Measurements, Recurring | Futures
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	72,723
Derivative liabilities		1,527
Fair Value, Measurements, Recurring | Futures | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	72,723
Derivative liabilities		1,527
Fair Value, Measurements, Recurring | Futures | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	0
Derivative liabilities		0
Fair Value, Measurements, Recurring | Futures | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset	$ 0
Derivative liabilities		$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments Level 3 (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)percent
Measurement Input, Prepayment Rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Debt Securities, Available-for-sale, Measurement Input | percent	0.10
Loans Held-for-sale, Measurement Input | percent	0.10
Measurement Input, Default Rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Debt Securities, Available-for-sale, Measurement Input | percent	0.02
Loans Held-for-sale, Measurement Input | percent	0.02
Measurement Input, Loss Severity
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Debt Securities, Available-for-sale, Measurement Input | percent	0.20
Loans Held-for-sale, Measurement Input | percent	0.20
Measurement Input, Discount Rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Debt Securities, Available-for-sale, Measurement Input | percent	0.070
Loans Held-for-sale, Measurement Input | percent	0.070
Non-Agency MBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	$ 1,275
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)	(57)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(145)
Balance at the end of the period	1,143
Loans Receivable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of the period	6,264
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings	22
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(488)
Balance at the end of the period	5,749
Interest Income | Non-Agency MBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Accretion (amortization)	70
Interest Income | Loans Receivable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Accretion (amortization)	$ (5)

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands

Apr. 01, 2021

Mar. 22, 2021

Mar. 11, 2021

Mar. 01, 2021

Feb. 22, 2021

Feb. 11, 2021

Feb. 01, 2021

Jan. 25, 2021

Jan. 13, 2021

Mar. 31, 2021

Feb. 28, 2021

Jan. 31, 2021

Mar. 31, 2021

Mar. 31, 2020

Feb. 15, 2021

Dec. 31, 2020

Mar. 16, 2020

Class of Stock [Line Items]

Preferred Stock, Shares Authorized

50,000,000

50,000,000

50,000,000

Preferred Stock, Par or Stated Value Per Share

$ 0.01

$ 0.01

$ 0.01

Preferred Stock, Shares Outstanding

4,460,000

4,460,000

7,248,330

Preferred stock redemption charge

$ 2,987

$ 3,914

Dividends Payable, Date Declared, Month and Year

Mar. 11, 2021

Feb. 11, 2021

Jan. 13, 2021

Common Stock, Dividends, Per Share, Declared

$ 0.13

$ 0.13

$ 0.13

Series B Preferred Stock

Class of Stock [Line Items]

Preferred Stock, Shares Outstanding

2,788,330

Preferred Stock, Redemption Price Per Share

$ 25.15

Preferred Stock, Liquidation Preference Per Share

$ 25

Series C Preferred Stock

Class of Stock [Line Items]

Preferred Stock, Shares Authorized

6,600,000

6,600,000

Stock issuance, shares

4,460,000

Preferred Stock, Liquidation Preference Per Share

$ 25

$ 25

Preferred Stock, Dividend Payment Terms

The Series C Preferred stock pays a cumulative cash dividend equivalent to 6.900% of the $25.00 liquidation preference per share each year until April 15, 2025 upon which date and thereafter, the Company will pay cumulative cash dividends at a percentage of the $25.00 liquidation value per share equal to an annual floating rate of three-month LIBOR plus a spread of 5.461%.

Preferred Stock, Dividends Per Share, Declared

$ 0.43125

Common Stock

Class of Stock [Line Items]

Dividends Payable, Date of Record

Mar. 22, 2021

Feb. 22, 2021

Jan. 25, 2021

Dividends Payable, Date to be Paid

Apr. 1, 2021

Mar. 1, 2021

Feb. 1, 2021

Shareholders' Equity and Shar_3

Shareholders' Equity and Share-Based Compensation Share-based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based incentive plan, number of shares authorized for issuance	2,300,000
Stock-based compensation expense	$ 452	$ 307
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Rollforward]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition	2 years 1 month 6 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Rollforward]
Restricted stock outstanding as of beginning of period	281,761	119,213
Granted	16,722	67,511
Vested	(59,024)	(48,569)
Restricted stock outstanding as of end of period	239,459	138,155
Restricted stock as of beginning of period of period, nonvested, weighted average grant date fair value per share	$ 14.74	$ 18.56
Restricted stock granted, weighted average grant date fair value per share	19.03	17.10
Restricted stock vested, weighted average grant date fair value per share	18.02	19.02
Restricted stock as of end of period, nonvested, weighted average grant date fair value per share	$ 14.23	$ 17.69
Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount	$ 2,626