ARMOUR Residential REIT (ARR) 10-K 14 Feb 18 2017 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 13, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	Armour Residential REIT, Inc.
Entity Central Index Key	1,428,205
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		41,877,404
Entity Public Float			$ 1,016,598,050

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash	$ 265,232	$ 271,773
Cash collateral posted to counterparties	17,162	79,471
Agency Securities, available for sale, at fair value (including pledged securities of $7,094,766 at December 31, 2017 and $6,298,811 at December 31, 2016)	7,478,966	6,511,164
Derivatives, at fair value	37,211	9,837
Accrued interest receivable	22,165	18,452
Prepaid and other	1,600	1,667
Subordinated loans due from BUCKLER Securities LLC	105,000	0
Total Assets	8,928,917	7,978,161
Liabilities:
Repurchase agreements	7,555,917	6,818,453
Cash collateral posted by counterparties	29,593	3,774
Derivatives, at fair value	7,948	49,655
Accrued interest payable- repurchase agreements	6,452	6,934
Accounts payable and other accrued expenses	2,956	7,280
Total Liabilities	7,602,866	6,886,096
Commitments and contingencies (Note 10)
Preferred stock, $0.001 par value, 50,000 shares authorized;
Common stock, $0.001 par value, 125,000 shares authorized, 41,877 and 36,723 shares issued and outstanding at December 31, 2017 and December 31, 2016	42	37
Additional paid-in capital	2,709,335	2,560,242
Accumulated deficit	(1,363,223)	(1,439,088)
Accumulated other comprehensive loss	(20,111)	(29,134)
Total Stockholders’ Equity	1,326,051	1,092,065
Total Liabilities and Stockholders’ Equity	8,928,917	7,978,161
Series A Preferred Stock
Preferred stock, $0.001 par value, 50,000 shares authorized;
Preferred stock	2	2
Series B Preferred Stock
Preferred stock, $0.001 par value, 50,000 shares authorized;
Preferred stock	6	6
Credit Risk and Non-Agency Securities
Assets
Securities, trading, at fair value	975,829	1,052,170
Interest-Only Securities
Assets
Securities, trading, at fair value	$ 25,752	$ 33,627

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Agency securities pledged	$ 7,094,766	$ 6,298,811
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	125,000,000	125,000,000
Common stock, shares issued (in shares)	41,877,000	36,723,000
Common stock, shares outstanding (in shares)	41,877,000	36,723,000
Series A Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	9,610,000
Preferred stock, shares issued (in shares)	2,181,000	2,181,000
Preferred stock, shares outstanding (in shares)	2,181,000	2,181,000
Preferred stock, aggregate liquidation preference	$ 54,514	$ 54,514
Preferred stock, dividend rate	8.25%	8.25%
Series B Preferred Stock
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	7,650,000
Preferred stock, shares issued (in shares)	6,262,000	5,650,000
Preferred stock, shares outstanding (in shares)	6,262,000	5,650,000
Preferred stock, aggregate liquidation preference	$ 156,560	$ 141,250
Preferred stock, dividend rate	7.875%	7.875%
Credit Risk and Non-Agency Securities
Pledged securities	$ 974,372	$ 1,052,170

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Income:
Agency Securities, net of amortization of premium and fees		$ 196,301	$ 225,796	$ 365,300
Total Interest Income		254,433	263,995	365,300
Interest expense- repurchase agreements		(94,558)	(73,107)	(59,278)
Net Interest Income		159,875	190,888	306,022
Other Income (Loss):
Realized loss on sale of Agency Securities (reclassified from Other comprehensive income (loss))		(8,486)	(18,211)	(11,546)
Other than temporary impairment of Agency Securities (reclassified from Other comprehensive income (loss))		(13,707)	(6,540)	0
Bargain purchase price on acquisition of JAVELIN		0	6,484	0
Subtotal		40,513	47,284	(11,546)
Realized gain (loss) on derivatives	[1]	(22,675)	(452,398)	(107,070)
Unrealized gain (loss) on derivatives		39,272	206,212	(181,662)
Subtotal		16,597	(246,186)	(288,732)
Total Other Income (Loss)		57,110	(198,902)	(300,278)
Expenses:
Management fees		26,582	26,070	27,292
Professional fees		4,578	5,253	3,117
Insurance		836	1,010	690
Compensation		2,298	2,260	2,291
Other		1,537	2,910	3,559
Total Expenses		35,831	37,503	36,949
Net Income (Loss)		181,154	(45,517)	(31,205)
Dividends on preferred stock		(15,880)	(15,622)	(15,622)
Net Income (Loss) available (related) to common stockholders		$ 165,274	$ (61,139)	$ (46,827)
Net Income (Loss) per share available (related) to common stockholders (Note 13):
Basic (in dollars per share)		$ 4.22	$ (1.67)	$ (1.09)
Diluted (in dollars per share)		4.17	(1.67)	(1.09)
Dividends declared per common share (in dollars per share)		$ 2.28	$ 3.02	$ 3.89
Weighted average common shares outstanding:
Basic (in shares)		39,170	36,698	42,780
Diluted (in shares)		39,642	36,698	42,780
Credit Risk and Non-Agency Securities
Interest Income:
Trading securities, interest income		$ 55,969	$ 36,573	$ 0
Other Income (Loss):
Gain (loss) on trading securities		65,672	59,120	0
Interest-Only Securities
Interest Income:
Trading securities, interest income		2,163	1,626	0
Other Income (Loss):
Gain (loss) on trading securities		$ (2,966)	$ 6,431	$ 0
[1]	Interest expense related to our interest rate swap contracts is recorded as realized loss on derivatives on the consolidated statements of operations. For additional information, see Note 9 to the consolidated financial statements.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 181,154	$ (45,517)	$ (31,205)
Other comprehensive income (loss):
Reclassification adjustment for realized loss on sale of available for sale Agency Securities	8,486	18,211	11,546
Reclassification adjustment for other than temporary impairment of available for sale Agency Securities	13,707	6,540	0
Net unrealized gain (loss) on available for sale Agency Securities	(13,170)	13,417	(163,202)
Other comprehensive income (loss)	9,023	38,168	(151,656)
Comprehensive Income (Loss)	$ 190,177	$ (7,349)	$ (182,861)

Consolidated Statement of Stock

Consolidated Statement of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Series A Preferred Stock	Series B Preferred Stock	Preferred StockSeries A Preferred Stock	Preferred StockSeries B Preferred Stock	Additional Paid-in Capital	Additional Paid-in CapitalSeries A Preferred Stock	Additional Paid-in CapitalSeries B Preferred Stock	Additional Paid-in CapitalCommon Stock	Common Stock	Accumulated Deficit	Accumulated DeficitSeries A Preferred Stock	Accumulated DeficitSeries B Preferred Stock	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2014				2,181	5,650					44,145
Balance at Dec. 31, 2014	$ 1,749,291			$ 2	$ 6	$ 2,717,854	$ 53,172	$ 136,547	$ 2,528,135	$ 44	$ (1,052,969)			$ 84,354
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred dividends		$ (4,498)	$ (11,124)									$ (4,498)	$ (11,124)
Common stock dividends	(167,142)										(167,142)
Issuance of common stock, net (in shares)										6
Issuance of common stock, net	147					147			147
Stock based compensation, net of withholding requirements (in shares)										41
Stock based compensation, net of withholding requirements	$ 953					952			952	$ 1
Common stock repurchased (in shares)	(7,510)									(7,510)
Common stock repurchased	$ (159,600)					(159,592)			(159,592)	$ (8)
Net Income	(31,205)										(31,205)
Other comprehensive income	(151,656)													(151,656)
Balance (in shares) at Dec. 31, 2015				2,181	5,650					36,682
Balance at Dec. 31, 2015	1,225,166			$ 2	$ 6	2,559,361	53,172	136,547	2,369,642	$ 37	(1,266,938)			(67,302)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred dividends		(4,498)	(11,124)									(4,498)	(11,124)
Common stock dividends	(111,011)										(111,011)
Stock based compensation, net of withholding requirements (in shares)										41
Stock based compensation, net of withholding requirements	881					881			881
Net Income	(45,517)										(45,517)
Other comprehensive income	38,168													38,168
Balance (in shares) at Dec. 31, 2016				2,181	5,650					36,723
Balance at Dec. 31, 2016	1,092,065			$ 2	$ 6	2,560,242	53,172	136,547	2,370,523	$ 37	(1,439,088)			(29,134)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred dividends		$ (4,498)	(11,382)									$ (4,498)	$ (11,382)
Common stock dividends	(89,409)										(89,409)
Issuance of Series B Preferred stock, net (in shares)					612
Issuance of Series B Preferred stock, net	14,968		$ 0			14,968		14,968
Issuance of common stock, net (in shares)										5,119
Issuance of common stock, net	133,193					133,188			133,188	$ 5
Stock based compensation, net of withholding requirements (in shares)										35
Stock based compensation, net of withholding requirements	937					937			937
Net Income	181,154										181,154
Other comprehensive income	9,023													9,023
Balance (in shares) at Dec. 31, 2017				2,181	6,262					41,877
Balance at Dec. 31, 2017	$ 1,326,051			$ 2	$ 6	$ 2,709,335	$ 53,172	$ 151,515	$ 2,504,648	$ 42	$ (1,363,223)			$ (20,111)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows From Operating Activities:
Net Income (Loss)	$ 181,154,000	$ (45,517,000)	$ (31,205,000)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Net amortization of premium on Agency Securities	44,838,000	77,827,000	109,589,000
Accretion of net discount on Credit Risk and Non-Agency Securities	(3,866,000)	(2,118,000)	0
Realized loss on sale of Agency Securities	8,486,000	18,211,000	11,546,000
Other than temporary impairment of Agency Securities	13,707,000	6,540,000	0
Stock based compensation	937,000	881,000	953,000
Bargain purchase price on acquisition of JAVELIN	0	(6,484,000)	0
Changes in operating assets and liabilities:
(Increase) decrease in accrued interest receivable	(3,713,000)	17,415,000	6,816,000
(Increase) decrease in prepaid and other assets	(100,000)	3,622,000	(2,881,000)
(Increase) decrease in derivatives, at fair value	(69,081,000)	(210,034,000)	155,427,000
Increase (decrease) in accrued interest payable- repurchase agreements	(482,000)	(1,703,000)	712,000
Decrease in accounts payable and other accrued expenses	(4,003,000)	(4,284,000)	(12,702,000)
Net cash provided by (used in) operating activities	110,079,000	(203,426,000)	238,255,000
Cash Flows From Investing Activities:
Purchases of Agency Securities	(5,813,389,000)	(2,201,480,000)	(5,145,847,000)
Principal repayments of Agency Securities	775,181,000	1,337,671,000	1,910,795,000
Principal repayments of Credit Risk and Non-Agency Securities	145,731,000	53,033,000	0
Proceeds from sales of Agency Securities	4,012,398,000	7,195,157,000	5,614,195,000
(Increase) decrease in cash collateral	88,128,000	212,703,000	(183,035,000)
Net cash used in the acquisition of JAVELIN	0	(73,174,000)	0
Subordinated loans due from BUCKLER	(105,000,000)	0	0
Net cash provided by (used in) investing activities	(896,803,000)	5,668,200,000	2,196,108,000
Cash Flows From Financing Activities:
Issuance of common stock, net of expenses	133,193,000	0	147,000
Proceeds from repurchase agreements	141,685,213,000	139,917,180,000	90,941,440,000
Principal repayments on repurchase agreements	(140,947,749,000)	(145,258,815,000)	(93,252,880,000)
Common stock dividends paid	(89,409,000)	(111,011,000)	(167,142,000)
Common stock repurchased	0	(14,658,000)	(144,942,000)
Net cash provided by (used in) financing activities	780,183,000	(5,482,926,000)	(2,638,999,000)
Net decrease in cash	(6,541,000)	(18,152,000)	(204,636,000)
Cash - beginning of year	271,773,000	289,925,000	494,561,000
Cash - end of year	265,232,000	271,773,000	289,925,000
Supplemental Disclosure:
Cash paid during the year for interest	164,913,000	193,944,000	218,503,000
Non-Cash Investing and Financing Activities:
Net unrealized gain (loss) on available for sale Agency Securities	(13,170,000)	13,417,000	(163,202,000)
Amounts receivable for issuance of preferred stock	153,000	0	0
Amounts payable for common stock repurchased	0	0	(14,658,000)
Series A Preferred Stock
Cash Flows From Financing Activities:
Preferred dividends paid	(4,497,600)	(4,497,600)	(4,498,000)
Series B Preferred Stock
Cash Flows From Financing Activities:
Issuance of Series B Preferred stock, net of expenses	14,815,000	0	0
Preferred dividends paid	(11,382,000)	(11,124,000)	(11,124,000)
Interest-Only Securities
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Net amortization of premium on Agency Securities	4,908,000	7,769,000	0
Gain (loss) on trading securities	2,966,000	(6,431,000)	0
Cash Flows From Investing Activities:
Purchases of trading securities	0	(101,947,000)	0
Proceeds from sale of trading securities	0	66,982,000	0
Credit Risk and Non-Agency Securities
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Gain (loss) on trading securities	(65,672,000)	(59,120,000)	0
Cash Flows From Investing Activities:
Purchases of trading securities	(8,224,000)	(882,588,000)	0
Proceeds from sale of trading securities	$ 8,372,000	$ 61,843,000	$ 0

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Note 1 -Basis of Presentation The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the U.S. (“GAAP”). The consolidated financial statements include the accounts of ARMOUR Residential REIT, Inc. and its subsidiaries including the results of JAVELIN Mortgage Investment Corp. since its acquisition on April 6, 2016 (see also Note 16 “ Acquisition of JAVELIN Mortgage Investment Corp. ”). All intercompany accounts and transactions have been eliminated. 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 disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates affecting the accompanying consolidated financial statements include the valuation of MBS (as defined below), including an assessment of whether other-than-temporary impairment (“OTTI”) exists, and derivative instruments.

Organization and Nature of Busi

Organization and Nature of Business Operations	12 Months Ended
	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Business Operations	Note 2 -Organization and Nature of Business Operations References to “we,” “us,” “our,” or the “Company” are to ARMOUR Residential REIT, Inc. (“ARMOUR”) and its subsidiaries. References to “ACM” are to ARMOUR Capital Management LP, a Delaware limited partnership. Refer to the Glossary of Terms for definitions of capitalized terms and abbreviations used in this report. ARMOUR is an externally managed Maryland corporation incorporated in 2008. The Company is managed by ACM, an investment advisor registered with the SEC (see Note 10 -Commitments and Contingencies and Note 15 -Related Party Transactions for additional discussion). We invest in residential mortgage backed securities issued or guaranteed by a United States (“U.S.”) Government-sponsored entity (“GSE”), such as the Federal National Mortgage Association (Fannie Mae), the Federal Home Loan Mortgage Corporation (Freddie Mac) or a government agency such as the Government National Mortgage Administration (Ginnie Mae) (collectively, “Agency Securities”). We also invest in Interest-only Securities, which are the interest portion of Agency Securities, that is separated and sold individually from the principal portion of the same payment. Other securities backed by residential mortgages in which we invest, for which the payment of principal and interest is not guaranteed by a GSE or government agency (collectively, “Credit Risk and Non-Agency Securities” and together with Agency Securities and Interest-only Securities, “MBS”), may benefit from credit enhancement derived from structural elements such as subordination, over collateralization or insurance. Our MBS portfolio consists primarily of Agency Securities backed by fixed rate home loans. From time to time, a portion of our assets may be invested in Agency Securities backed by hybrid adjustable rate and adjustable rate home loans as well as unsecured notes and bonds issued by GSEs, U.S. Treasuries and money market instruments, subject to certain income tests we must satisfy for our qualification as a real estate investment trust (“REIT”). We have elected to be taxed as a REIT under the Internal Revenue Code, as amended (“the Code”). Our qualification as a REIT depends on our ability to meet, on a continuing basis, various complex requirements under the Code relating to, among other things, the sources of our gross income, the composition and values of our assets, our distribution levels and the concentration of ownership of our capital stock. We believe that we are organized in conformity with the requirements for qualification as a REIT under the Code and our manner of operations enables us to meet the requirements for taxation as a REIT for federal income tax purposes. As a REIT, we will generally not be subject to federal income tax on the REIT taxable income that we currently distribute to our stockholders. If we fail to qualify as a REIT in any taxable year and do not qualify for certain statutory relief provisions, we will be subject to federal income tax at regular corporate rates. Even if we qualify as a REIT for federal income tax purposes, we may still be subject to some federal, state and local taxes on our income.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 3 -Summary of Significant Accounting Policies Cash Cash includes cash on deposit with financial institutions. We may maintain deposits in federally insured financial institutions in excess of federally insured limits. However, management believes we are not exposed to significant credit risk 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 cash posted by us to counterparties or posted by counterparties to us as collateral. Cash collateral posted to/by counterparties may include collateral for interest rate swap contracts (including swaptions and basis swap contracts), Eurodollar Futures Contracts (“Futures Contracts”) and repurchase agreements on our MBS and our Agency Securities purchased or sold on a to-be-announced basis (“TBA Agency Securities”). MBS, at Fair Value We generally intend to hold most of our MBS for extended periods of time. We may, from time to time, sell any of our MBS as part of the overall management of our MBS portfolio. Management determines the appropriate classifications of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. Purchases and sales of our MBS are recorded on the trade date. Agency Securities, Available For Sale - At December 31, 2017 and December 31, 2016 , all of our Agency Securities were classified as available for sale securities. Agency Securities classified as available for sale are reported at their estimated fair values with unrealized gains and losses excluded from earnings and reported as part of the consolidated statements of comprehensive income (loss). Credit Risk and Non-Agency Securities, Trading - At December 31, 2017 and December 31, 2016 , all of our Credit Risk and Non-Agency Securities were classified as trading securities. Credit Risk and Non-Agency Securities classified as trading are reported at their estimated fair values with unrealized gains and losses included in Other Income (Loss) as a component of the consolidated statements of operations. Interest-only Securities, Trading - At December 31, 2017 and December 31, 2016 , all of our Interest-only Securities were classified as trading securities. Interest-only Securities represent the right to receive a specified proportion of the contractual interest flows of specific Agency MBS. Interest-only Securities classified as trading are reported at their estimated fair values with unrealized gains and losses included in Other Income (Loss) as a component of the consolidated statements of operations. Receivables and Payables for Unsettled Sales and Purchases We account for purchases and sales of securities on the trade date, including purchases and sales for forward settlement. Receivables and payables for unsettled trades represent the agreed trade price multiplied by the outstanding balance of the securities at the balance sheet date. Accrued Interest Receivable and Payable Accrued interest receivable includes interest accrued between payment dates on MBS. Accrued interest payable includes interest payable on our repurchase agreements and may, at certain times, contain interest payable on U.S. Treasury Securities sold short. Repurchase Agreements We finance the acquisition of our MBS through the use of repurchase agreements. Our repurchase agreements are secured by our MBS and bear interest rates that have historically moved in close relationship to the Federal Funds Rate and the London Interbank Offered Rate (“LIBOR”). Under these repurchase agreements, we sell MBS to a lender and agree to repurchase the same MBS in the future for a price that is higher than the original sales price. The difference between the sales price that we receive and the repurchase price that we pay represents interest paid to the lender. A repurchase agreement operates as a financing arrangement under which we pledge our MBS as collateral to secure a loan which is equal in value to a specified percentage of the estimated fair value of the pledged collateral. We retain beneficial ownership of the pledged collateral. At the maturity of a repurchase agreement, we are required to repay the loan and concurrently receive back our pledged collateral from the lender or, with the consent of the lender, we may renew such agreement at the then prevailing interest rate. The repurchase agreements may require us to pledge additional assets to the lender in the event the estimated fair value of the existing pledged collateral declines. In addition to the repurchase agreement financing discussed above, at certain times we have entered into reverse repurchase agreements with certain of our repurchase agreement counterparties. Under a typical reverse repurchase agreement, we purchase U.S. Treasury Securities from a borrower in exchange for cash and agree to sell the same securities in the future in exchange for a price that is higher than the original purchase price. The difference between the purchase price originally paid and the sale price represents interest received from the borrower. Reverse repurchase agreement receivables and repurchase agreement liabilities are presented net when they meet certain criteria, including being with the same counterparty, being governed by the same master repurchase agreement (“MRA”), settlement through the same brokerage or clearing account and maturing on the same day. We did not have any reverse repurchase agreements outstanding at December 31, 2017 and December 31, 2016 . Obligations to Return Securities Received as Collateral, at Fair Value At certain times, we also sell to third parties the U.S. Treasury Securities received as collateral for reverse repurchase agreements and recognize the resulting obligation to return said U.S. Treasury Securities as a liability on our consolidated balance sheets. Interest is recorded on the repurchase agreements, reverse repurchase agreements and U.S. Treasury Securities sold short on an accrual basis and presented as interest expense. Both parties to the transaction have the right to make daily margin calls based on changes in the fair value of the collateral received and/or pledged. We did not have any obligations to return securities received as collateral at December 31, 2017 and December 31, 2016 . Derivatives, at Fair Value We recognize all derivatives as either assets or liabilities at fair value on our consolidated balance sheets. All changes in the fair values of our derivatives are reflected in our consolidated statements of operations. We designate derivatives as hedges for tax purposes and any unrealized derivative gains or losses would not affect our distributable net taxable income. These transactions include interest rate swap contracts, interest rate swaptions and basis swap contracts. We also may utilize forward contracts for the purchase or sale of TBA Agency Securities. We account for TBA Agency Securities as derivative instruments if it is reasonably possible that we will not take or make physical delivery of the Agency Security upon settlement of the contract. We account for TBA dollar roll transactions as a series of derivative transactions. We may also purchase and sell TBA Agency Securities as a means of investing in and financing Agency Securities (thereby increasing our “at risk” leverage) or as a means of disposing of or reducing our exposure to Agency Securities (thereby reducing our “at risk” leverage). Pursuant to TBA Agency Securities, we agree to purchase or sell, for future delivery, Agency Securities 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 TBA settlement date. We may also choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting short or long position (referred to as a “pair off”), net settling the paired off positions for cash, and simultaneously purchasing or selling a similar TBA Agency Security for a later settlement date. This transaction is commonly referred to as a “dollar roll.” When it is reasonably possible that we will pair off a TBA Agency Security, we account for that contract as a derivative. Revenue Recognition Agency Securities, Available For Sale - Interest income is earned and recognized on Agency Securities based on their unpaid principal amounts and their contractual terms. Recognition of interest income commences on the settlement date of the purchase transaction and continues through the settlement date of the sale transaction. Premiums and discounts associated with the purchase of Multi-Family MBS, which are generally not subject to prepayment, are amortized or accreted into interest income over the contractual lives of the securities using a level yield method. Premiums and discounts associated with the purchase of other Agency Securities are amortized or accreted into interest income over the actual lives of the securities, reflecting actual prepayments as they occur. Fair Value of Agency Securities: We invest in Agency Securities representing interests in or obligations backed by pools of fixed rate, hybrid adjustable rate and adjustable rate mortgage loans. GAAP requires us to classify our investments as either trading, available for sale or held to maturity securities. Management determines the appropriate classifications of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. We currently classify all of our Agency Securities as available for sale. Agency Securities classified as available for sale are reported at their estimated fair values with unrealized gains and losses excluded from earnings and reported as part of the statements of comprehensive income (loss). Security purchase and sale transactions, including purchase of TBA Agency Securities, are recorded on the trade date to the extent it is probable that we will take or make timely physical delivery of the related securities. Gains or losses realized from the sale of securities are included in income and are determined using the specific identification method. Impairment of Assets: We evaluate Agency Securities for other than temporary impairment at least on a quarterly basis and more frequently when economic or market concerns warrant such evaluation. We consider an impairment to be other than temporary if we (1) have the intent to sell the Agency Securities, (2) believe it is more likely than not that we will be required to sell the securities before recovery (for example, because of liquidity requirements or contractual obligations) or (3) a credit loss exists. Impairment losses recognized establish a new cost basis for the related Agency Securities. Credit Risk and Non-Agency Securities and Interest-Only Securities, Trading - Interest income on Credit Risk and Non-Agency Securities and Interest-only Securities is recognized using the effective yield method over the life of the securities based on the future cash flows expected to be received. Future cash flow projections and related effective yields are determined for each security and updated quarterly. Other than temporary impairments, which establish a new cost basis in the security for purposes of calculating effective yields, are recognized when the fair value of a security is less than its cost basis and there has been an adverse change in the future cash flows expected to be received. Other changes in future cash flows expected to be received are recognized prospectively over the remaining life of the security. Comprehensive Income (Loss) Comprehensive income (loss) refers to changes in equity during a period from transactions and other events and circumstances from non-owner sources. It includes all changes in equity during a period, except those resulting from investments by owners and distributions to owners.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2017
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Note 4 -Recent Accounting Pronouncements In August 2017, the Financial Accounting Standards Board issued ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities . The standard amends the hedge accounting recognition and presentation requirements in ASC 815. The standard is effective for fiscal years beginning after December 15, 2018 and interim periods therein, however, early adoption is permitted upon its issuance. The Company is currently assessing the impact of the standard and whether it may apply hedge accounting in the future. In February 2016, the Financial Accounting Standards Board issued ASU 2016-02, Leases (Topic 842). The standard introduces a new lessee model that will require most leases to be recorded on the balance sheet recognizing a right-of-use lease asset and a liability to make lease payments. The standard will be effective for annual periods beginning after December 15, 2018. As the Company has no leases this standard will have no impact on the consolidated financial statements in future periods. In July 2016, the Financial Accounting Standards Board issued ASU 2016-13, Financial Instruments–Credit Losses (Topic 326) . The standard introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. The standard will apply to (1) loans, accounts receivable, trade receivables, and other financial assets measured at amortized cost, (2) loan commitments and certain other off–balance sheet credit exposures, (3) debt securities and other financial assets measured at fair value through other comprehensive income, and (4) beneficial interests in securitized financial assets. The standard is effective for fiscal years beginning after December 15, 2019. The Company is assessing the impact of this standard but does not expect it to have significant impact on the consolidated financial statements. However, the impact on the consolidated financial statements will depend on the debt securities held by the Company on the date of the adoption.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Note 5 -Fair Value of Financial Instruments Our valuation techniques for financial instruments use observable and unobservable inputs. Observable inputs reflect readily obtainable data from third party sources, while unobservable inputs reflect management’s market assumptions. The Accounting Standards Codification Topic No. 820, “Fair Value Measurement,” classifies these inputs into the following hierarchy: Level 1 Input s - Quoted prices for identical instruments in active markets. Level 2 Inputs - Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable. Level 3 Inputs - Prices determined using significant unobservable inputs. Unobservable inputs may be used in situations where quoted prices or observable inputs are unavailable (for example, when there is little or no market activity for an investment at the end of the period). Unobservable inputs reflect management’s assumptions about the factors that market participants would use in pricing an asset or liability, and would be based on the best information available. The following describes the valuation methodologies used for our assets and liabilities measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy. Any transfers between levels are assumed to occur at the beginning of the reporting period. Cash - Cash includes cash on deposit with financial institutions. The carrying amount of cash is deemed to be its fair value and is classified as Level 1. Cash balances posted by us to counterparties or posted by counterparties to us as collateral are classified as Level 2 because they are integrally related to the Company's repurchase financing and interest rate swap agreements, which are classified as Level 2. Agency Securities, Available for Sale - Fair value for the Agency Securities in our MBS portfolio is based on obtaining a valuation for each Agency Security from third party pricing services and/or dealer quotes. The third party pricing services use common market pricing methods that may include pricing models that may incorporate such factors as coupons, prepayment speeds, spread to the Treasury curves and interest rate swap curves, duration, periodic and life caps and credit enhancement. If the fair value of an Agency Security is not available from the third party pricing services or such data appears unreliable, we obtain pricing indications from up to three dealers who make markets in similar Agency Securities. Management reviews pricing used to ensure that current market conditions are properly reflected. This review includes, but is not limited to, comparisons of similar market transactions or alternative third party pricing services, dealer pricing indications and comparisons to a third party pricing model. Fair values obtained from the third party pricing services for similar instruments are classified as Level 2 securities if the inputs to the pricing models used are consistent with the Level 2 definition. If quoted prices for a security are not reasonably available from the third party pricing service, but dealer pricing indications are, the security will be classified as a Level 2 security. If neither is available, management will determine the fair value based on characteristics of the security that we receive from the issuer and based on available market information and classify it as a Level 3 security. At December 31, 2017 and December 31, 2016 , all of our Agency Security fair values are classified as Level 2 based on the inputs used by our third party pricing services and dealer quotes. Credit Risk and Non-Agency Securities Trading - The fair value for the Credit Risk and Non-Agency Securities in our MBS portfolio is based on obtaining a valuation for each Credit Risk and Non-Agency Security from third party pricing services and/or dealer quotes. The third party pricing services incorporate such factors as collateral type, bond structure and priority of payments, coupons, prepayment speeds, defaults, delinquencies and severities. If the fair value of a Credit Risk and Non-Agency Security is not available from the third party pricing services or such data appears unreliable, we obtain pricing indications from up to three dealers who make markets in similar Credit Risk and Non-Agency Securities. Management reviews pricing used to ensure that current market conditions are properly reflected. This review includes, but is not limited to, comparisons of similar market transactions or alternative third party pricing services, dealer pricing indications and comparisons to fair value determined using a third party pricing model. Fair values obtained from the third party pricing services for similar instruments are classified as Level 2 securities if the inputs to the pricing models used are consistent with the Level 2 definition. If quoted prices for a security are not reasonably available from the third party pricing service, but dealer pricing indications are, the security will be classified as a Level 2 security. If neither is available, management will determine the fair value based on characteristics of the security that we receive from the issuer and based on available market information and classify it as a Level 3 security. At December 31, 2017 all of our Credit Risk and Non-Agency Securities are classified as Level 2 based on the inputs used by our third party pricing services and dealer quotes. At December 31, 2016 , all of our Credit Risk and Non-Agency Securities fair values were classified as Level 3. Interest-Only Securities Trading - The fair value for the Interest-Only Securities in our MBS portfolio is based on obtaining a valuation for each Interest-Only Security from third party pricing services and/or dealer quotes. The third party pricing services use common market pricing methods that may include pricing models consistent with those models used to price Agency Securities underlying the Interest-Only Securities that may incorporate such factors as coupons, prepayment speeds, spread to the Treasury curves and interest rate swap curves, duration, periodic and life caps and credit enhancement. If the fair value of an Interest-Only Security is not available from the third party pricing services or such data appears unreliable, we obtain pricing indications from up to three dealers who make markets in similar Interest-Only Securities. Management reviews pricing used to ensure that current market conditions are properly reflected. This review includes, but is not limited to, comparisons of similar market transactions or alternative third party pricing services, dealer pricing indications and comparisons to a third party pricing model. Fair values obtained from the third party pricing services for similar instruments are classified as Level 2 securities if the inputs to the pricing models used are consistent with the Level 2 definition. If quoted prices for a security are not reasonably available from the third party pricing service, but dealer pricing indications are, the security will be classified as a Level 2 security. If neither is available, management will determine the fair value based on characteristics of the security that we receive from the issuer and based on available market information and classify it as a Level 3 security. At December 31, 2017 , all of our Interest-Only Security fair values are classified as Level 2 based on the inputs used by our third party pricing services and dealer quotes. Receivables and Payables for Unsettled Sales and Purchases - The carrying amount is generally deemed to be fair value because of the relatively short time to settlement. Such receivables and payables are classified as Level 2 because they are effectively secured by the related securities and could potentially be subject to counterparty credit considerations. Repurchase Agreements - The fair value of repurchase agreements reflects the present value of the contractual cash flows discounted at the estimated LIBOR based market interest rates at the valuation date for repurchase agreements with a term equivalent to the remaining term to interest rate repricing, which may be at maturity, of our repurchase agreements. The fair value of the repurchase agreements approximates their carrying amount due to the short-term nature of these financial instruments. Our repurchase agreements are classified as Level 2. Obligations to Return Securities Received as Collateral - The fair value of the obligations to return securities received as collateral are based upon the prices of the related U.S. Treasury Securities obtained from a third party pricing service. Such obligations are classified as Level 1. Derivative Transactions - The fair values of our interest rate swap contracts, interest rate swaptions and basis swaps are valued using information provided by third party pricing services that incorporate common market pricing methods that may include current interest rate curves, forward interest rate curves and market spreads to interest rate curves. We estimate the fair value of TBA Agency Securities based on similar methods used to value our Agency Securities. Management compares the pricing information received to dealer quotes to ensure that the current market conditions are properly reflected. The fair values of our interest rate swap contracts, interest rate swaptions, basis swap contracts and TBA Agency Securities are classified as Level 2. The following tables provide a summary of our assets and liabilities that are measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016 . Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance at December 31, 2017 Assets at Fair Value: Agency Securities, available for sale $ — $ 7,478,966 $ — $ 7,478,966 Credit Risk and Non-Agency Securities, trading $ — $ 975,829 $ — $ 975,829 Interest-Only Securities, trading $ — $ 25,752 $ — $ 25,752 Derivatives $ — $ 37,211 $ — $ 37,211 Liabilities at Fair Value: Derivatives $ — $ 7,948 $ — $ 7,948 At the beginning of the third quarter 2017, we determined that third party pricing services and or/dealer quotes available for Credit Risk and Non-Agency Securities meet the criteria for Level 2 classification. Fair values obtained from third party pricing services for similar instruments are classified as Level 2 securities, if the inputs to the pricing model used is consistent with the Level 2 definition. We transferred the securities to Level 2 from Level 3 at the commencement of the third quarter in 2017. Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance at December 31, 2016 Assets at Fair Value: Agency Securities, available for sale $ — $ 6,511,164 $ — $ 6,511,164 Credit Risk and Non-Agency Securities, trading $ — $ — $ 1,052,170 $ 1,052,170 Interest-Only Securities, trading $ — $ 33,627 $ — $ 33,627 Derivatives $ — $ 9,837 $ — $ 9,837 Liabilities at Fair Value: Derivatives $ — $ 49,655 $ — $ 49,655 There were no transfers of assets or liabilities between the levels of the fair value hierarchy during the year ended December 31, 2016 . The following tables provide a summary of the carrying values and fair values of our financial assets and liabilities not carried at fair value but for which fair value is required to be disclosed at December 31, 2017 and December 31, 2016 . December 31, 2017 Fair Value Measurements using: Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash $ 265,232 $ 265,232 $ 265,232 $ — $ — Cash collateral posted to counterparties $ 17,162 $ 17,162 $ — $ 17,162 $ — Accrued interest receivable $ 22,165 $ 22,165 $ — $ 22,165 $ — Subordinated loans due from BUCKLER Securities LLC $ 105,000 $ 105,000 $ — $ 105,000 — Financial Liabilities: Repurchase agreements $ 7,555,917 $ 7,555,917 $ — $ 7,555,917 $ — Cash collateral posted by counterparties $ 29,593 $ 29,593 $ — $ 29,593 $ — Accrued interest payable- repurchase agreements $ 6,452 $ 6,452 $ — $ 6,452 $ — December 31, 2016 Fair Value Measurements using: Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash $ 271,773 $ 271,773 $ 271,773 $ — $ — Cash collateral posted to counterparties $ 79,471 $ 79,471 $ — $ 79,471 $ — Accrued interest receivable $ 18,452 $ 18,452 $ — $ 18,452 $ — Financial Liabilities: Repurchase agreements $ 6,818,453 $ 6,818,453 $ — $ 6,818,453 $ — Cash collateral posted by counterparties $ 3,774 $ 3,774 $ — $ 3,774 $ — Accrued interest payable- repurchase agreements $ 6,934 $ 6,934 $ — $ 6,934 $ — The following table provides a summary of the changes in Level 3 assets measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016 . For the Years Ended Credit Risk and Non-Agency Securities December 31, 2017 December 31, 2016 Balance, beginning of year (1) $ 1,052,170 $ — Credit Risk and Non-Agency Securities acquired in the acquisition of JAVELIN, at fair value — 223,220 Purchases of Credit Risk and Non-Agency Securities, at cost 8,224 882,588 Principal repayments of Credit Risk and Non-Agency Securities (135,617 ) (53,033 ) Proceeds from the sale of Credit Risk and Non-Agency Securities (8,372 ) (61,843 ) Gain on Credit Risk and Non-Agency Securities 46,924 59,120 Accretion of net discount on Credit Risk and Non-Agency Securities 3,187 2,118 Level 3 transferred to Level 2 (966,516 ) — Balance, end of year $ — $ 1,052,170 Gain on Credit Risk and Non-Agency Securities $ 54,495 $ 59,120 (1) We did not have any Level 3 assets at December 31, 2015 . The significant unobservable inputs used in the fair value measurement of our Level 3 Credit Risk and Non-Agency Securities at December 31, 2016 , included assumptions for underlying loan collateral, cumulative default rates and loss severities in the event of default, as well as discount rates. The following table presents the range of our estimates of cumulative default and loss severities, together with the discount rates implicit in our Level 3 Credit Risk and Non-Agency Securities Security fair values at December 31, 2016 . Unobservable Level 3 Input Minimum Weighted Average Maximum Cumulative default 0.00 % 2.15 % 55.49 % Loss severity (life) 0.00 % 29.01 % 68.40 % Discount rate 3.62 % 4.47 % 5.50 % Delinquency (life) 0.00 % 4.84 % 50.10 % Voluntary prepayments (life) 1.50 % 8.72 % 14.60 % The table above includes the effects of the structural elements of our Credit Risk and Non-Agency Securities, such as subordination and over collateralization or insurance. Significant increases or decreases in any of these inputs in isolation would result in a significantly lower or higher fair value measurement. Generally, a change in the assumption used for the probability of cumulative default is accompanied by a directionally similar change in the assumption used for the delinquency and loss severity and a directionally opposite change in the assumption used for voluntary prepayment rates for the life of the security. However, given the interrelationship between loss estimates and the discount rate, overall Credit Risk and Non-Agency Securities Security market conditions would likely have a more significant impact on our Level 3 fair values than changes in any one unobservable input.

Agency Securities, Available fo

Agency Securities, Available for Sale	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Agency Securities, Available for Sale	Note 6 -Agency Securities, Available for Sale All of our Agency Securities are classified as available for sale and, as such, are reported at their estimated fair value and changes in fair value reported as part of the statements of comprehensive income (loss). At December 31, 2017 and December 31, 2016 , investments in Agency Securities accounted for 88.2% and 85.7% of our MBS portfolio. We evaluated our Agency Securities with unrealized losses at December 31, 2017 , December 31, 2016 and December 31, 2015 , to determine whether there was an other than temporary impairment. All of our Agency Securities are issued and guaranteed by GSEs or Ginnie Mae. The GSEs have a long term credit rating of AA+. At those dates, we also considered whether we intended to sell Agency Securities and whether it was more likely than not that we could meet our liquidity requirements and contractual obligations without selling Agency Securities. Results of this evaluation for the year ended December 31, 2017 : During 2017, we identified certain low yielding Agency Securities that we plan to replace with securities having more attractive returns as market conditions permit. Accordingly, we recognized losses totaling $13,707 in our consolidated financial statements of operations, thereby establishing a new cost basis for those Agency Securities with an aggregate fair value of $795,724 as of December 31, 2017 . We determined that there was no other than temporary impairment of our remaining Agency Securities as of December 31, 2017 Results of this evaluation for the year ended December 31, 2016 : Anticipating portfolio repositioning sales in January 2017, we concluded that the December 31, 2016 unrealized losses on certain of our 3.0% 15 -year fixed rate Agency Securities represented an other than temporary impairment. Accordingly, we recognized losses totaling $6,540 in our consolidated financial statements of operations, thereby establishing a new cost basis for those Agency Securities with an aggregate fair value of $785,285 as of December 31, 2016 . We determined that there was no other than temporary impairment of our remaining Agency Securities as of December 31, 2016 . Results of this evaluation for the year ended December 31, 2015 : No other than temporary impairment was recognized for the year ended December 31, 2015 because we determined that we 1) did not have the intent to sell the Agency Securities in an unrealized loss position, 2) did not believe it more likely than not that we were required to sell the securities before recovery (for example, because of liquidity requirements or contractual obligations), and/or (3) determined that a credit loss did not exist. At December 31, 2017 , we had the following Agency Securities in an unrealized gain or loss position as presented below. The components of the carrying value of our Agency Securities at December 31, 2017 are also presented below. Our Agency Securities had a weighted average coupon of 3.68% at December 31, 2017 . December 31, 2017 Amortized Cost Gross Unrealized Loss Gross Unrealized Gain Fair Value Percent of Total Fannie Mae ARMs & Hybrids $ 28,199 $ (229 ) $ 112 $ 28,082 0.38 % Multi-Family MBS 1,799,737 (5,132 ) 16,950 1,811,555 24.22 10 Year Fixed 60,634 (347 ) 137 60,424 0.81 15 Year Fixed 1,028,797 (4,955 ) 625 1,024,467 13.70 20 Year Fixed 29,832 (621 ) — 29,211 0.39 25 Year Fixed 9,367 (140 ) — 9,227 0.12 30 Year Fixed 2,938,655 (18,910 ) 431 2,920,176 39.05 Total Fannie Mae $ 5,895,221 $ (30,334 ) $ 18,255 $ 5,883,142 78.67 % Freddie Mac 10 Year Fixed 37,254 (158 ) 228 37,324 0.50 15 Year Fixed 354,878 (211 ) 787 355,454 4.75 25 Year Fixed 41,383 (857 ) — 40,526 0.54 30 Year Fixed 1,131,584 (7,300 ) — 1,124,284 15.03 Total Freddie Mac $ 1,565,099 $ (8,526 ) $ 1,015 $ 1,557,588 20.82 % Ginnie Mae ARMs & Hybrids 38,494 (532 ) 4 37,966 0.51 10 Year Fixed 263 — 7 270 0.00 Total Ginnie Mae $ 38,757 $ (532 ) $ 11 $ 38,236 0.51 % Total Agency Securities $ 7,499,077 $ (39,392 ) $ 19,281 $ 7,478,966 100.00 % At December 31, 2016 , we had the following securities in an unrealized gain or loss position as presented below. The components of the carrying value of our Agency Securities at December 31, 2016 are also presented below. Our Agency Securities had a weighted average coupon of 3.52% at December 31, 2016 . December 31, 2016 Amortized Cost Gross Unrealized Loss Gross Unrealized Gain Fair Value Percent of Total Fannie Mae ARMs & Hybrids $ 38,140 $ (174 ) $ 303 $ 38,269 0.60 % Multi-Family MBS 1,439,126 (5,677 ) 8,324 1,441,773 22.14 10 Year Fixed 93,440 (755 ) 335 93,020 1.43 15 Year Fixed 2,796,785 (10,424 ) 2,011 2,788,372 42.82 20 Year Fixed 338,017 (4,629 ) — 333,388 5.12 25 Year Fixed 12,126 (105 ) — 12,021 0.18 30 Year Fixed 1,062,718 (10,902 ) — 1,051,816 16.15 Total Fannie Mae $ 5,780,352 $ (32,666 ) $ 10,973 $ 5,758,659 88.44 % Freddie Mac 10 Year Fixed 48,030 (149 ) 501 48,382 0.75 15 Year Fixed 530,590 (5,876 ) 1,633 526,347 8.08 20 Year Fixed 19,503 (410 ) — 19,093 0.29 25 Year Fixed 115,442 (2,370 ) — 113,072 1.74 Total Freddie Mac $ 713,565 $ (8,805 ) $ 2,134 $ 706,894 10.86 % Ginnie Mae ARMs & Hybrids 46,092 (786 ) 3 45,309 0.70 10 Year Fixed 289 — 13 302 0.00 Total Ginnie Mae $ 46,381 $ (786 ) $ 16 $ 45,611 0.70 % Total Agency Securities $ 6,540,298 $ (42,257 ) $ 13,123 $ 6,511,164 100.00 % Recognition of interest income commences on the settlement date of the purchase transaction and continues through the settlement date of the sale transaction. Actual maturities of Agency Securities are generally shorter than stated contractual maturities because actual maturities of Agency Securities are affected by the contractual lives of the underlying mortgages, periodic payments of principal and prepayments of principal. The following table summarizes the weighted average lives of our Agency Securities at December 31, 2017 and December 31, 2016 . December 31, 2017 December 31, 2016 Weighted Average Life of all Agency Securities Fair Value Amortized Cost Fair Value Amortized Cost Less than one year $ — $ — $ 4 $ 5 Greater than or equal to one year and less than three years 29,126 29,269 17,773 17,998 Greater than or equal to three years and less than five years 1,353,036 1,353,998 3,237,524 3,248,401 Greater than or equal to five years 6,096,804 6,115,810 3,255,863 3,273,894 Total Agency Securities $ 7,478,966 $ 7,499,077 $ 6,511,164 $ 6,540,298 We use a third party model to calculate the weighted average lives of our Agency Securities. Weighted average life is calculated based on expectations for estimated prepayments for the underlying mortgage loans of our Agency Securities. These estimated prepayments are based on assumptions such as interest rates, current and future home prices, housing policy and borrower incentives. The weighted average lives of our Agency Securities at December 31, 2017 and December 31, 2016 in the table above are based upon market factors, assumptions, models and estimates from the third party model and also incorporate management’s judgment and experience. The actual weighted average lives of our Agency Securities could be longer or shorter than estimated. The following table presents the unrealized losses and estimated fair value of our Agency Securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2017 and December 31, 2016 . Unrealized Loss Position For: Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 $ 4,355,924 $ (28,906 ) $ 733,637 $ (10,486 ) $ 5,089,561 $ (39,392 ) December 31, 2016 $ 4,069,170 $ (41,045 ) $ 61,133 $ (1,212 ) $ 4,130,303 $ (42,257 ) During the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 we sold $4,012,398 , $7,195,157 and $5,367,123 of Agency Securities, which resulted in realized losses of $(8,486) , $(18,211) , and $(11,546) , respectively. Sales are executed to reposition our MBS portfolio and to reach our target level of liquidity. Note 7 -Credit Risk and Non-Agency Securities, Trading All of our Credit Risk and Non-Agency Securities are classified as trading securities and reported at their estimated fair value. Fair value changes are reported in the consolidated statements of operations in the period in which they occur. At December 31, 2017 and December 31, 2016 , investments in Credit Risk and Non-Agency Securities accounted for 11.5% and 13.9% of our MBS portfolio. The components of the carrying value of our Credit Risk and Non-Agency Securities at December 31, 2017 are presented in the table below. Credit Risk and Non-Agency Securities December 31, 2017 Fair Value Amortized Cost Principal Amount Weighted Average Coupon Credit Risk Transfer $ 870,494 $ 753,422 $ 764,172 6.05 % Legacy Prime Fixed 16,778 15,287 19,237 6.03 % Legacy ALT-A Fixed 54,727 48,516 65,920 5.85 % Legacy Prime Hybrid 10,469 9,517 11,452 3.17 % Legacy ALT-A Hybrid 4,660 3,895 4,901 3.47 % New Issue Prime Fixed 18,701 17,957 — 19,025 3.69 % Total Credit Risk and Non-Agency Securities $ 975,829 $ 848,594 $ 884,707 5.95 % The components of the carrying value of our Credit Risk and Non-Agency Securities at December 31, 2016 are presented in the table below. Credit Risk and Non-Agency Securities December 31, 2016 Fair Value Amortized Cost Principal Amount Weighted Average Coupon Credit Risk Transfer $ 821,343 $ 764,982 $ 778,216 5.26% NPL/RPL 122,802 121,869 122,561 3.80% Legacy Prime Fixed 19,954 19,406 24,409 6.03% Legacy ALT-A Fixed 59,253 56,776 76,151 5.85% Legacy Prime Hybrid 11,914 11,163 13,641 2.72% Legacy ALT-A Hybrid 6,039 5,669 6,956 3.01% New Issue Prime Fixed 10,865 10,708 11,324 3.66% Total Credit Risk and Non-Agency Securities $ 1,052,170 $ 990,573 $ 1,033,258 5.08% Our Credit Risk Transfer securities are collaterized by residential mortgage loans meeting agency criteria. However, our securities principal and interest are not guaranteed by the agencies. Credit Risk Transfer securities include tranches issued since 2014. Our NPL/RPL securities included tranches issued since 2015 were collaterized by non-performing and re-performing loans. Our Legacy and New Issue Prime Fixed securities are collaterized by residential mortgage loans not guaranteed by any agency. Legacy Prime Fixed, Legacy Alt-A Fixed securities include tranches issued between 2005-2007. New Issue Prime Fixed securities include tranches issued in 2013. The following table summarizes the weighted average lives of our Credit Risk and Non-Agency Securities at December 31, 2017 and December 31, 2016 . December 31, 2017 December 31, 2016 Weighted Average Life of all Credit Risk and Non-Agency Securities Fair Value Amortized Cost Fair Value Amortized Cost Less than one year $ — $ — $ — $ — Greater than or equal to one year and less than three years — — 122,802 121,869 Greater than or equal to three years and less than five years 169,189 149,436 94,839 88,750 Greater than or equal to five years 806,640 699,158 834,529 779,954 Total Credit Risk and Non-Agency Securities $ 975,829 $ 848,594 $ 1,052,170 $ 990,573 We use a third party model to calculate the weighted average lives of our Credit Risk and Non-Agency Securities. Weighted average life is calculated based on expectations for estimated prepayments for the underlying mortgage loans of our Credit Risk and Non-Agency Securities. These estimated prepayments are based on assumptions such as interest rates, current and future home prices, housing policy and borrower incentives. The weighted average lives of our Credit Risk and Non-Agency Securities at December 31, 2017 and December 31, 2016 , in the tables above are based upon market factors, assumptions, models and estimates from the third party model and also incorporate management’s judgment and experience. The actual weighted average lives of our Credit Risk and Non-Agency Securities could be longer or shorter than estimated. The following table presents the unrealized losses and estimated fair value of our Credit Risk and Non-Agency Securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2017 and December 31, 2016 . Unrealized Loss Position For: Less than 12 Months 12 Months or More Total As of Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 $ — $ — $ — $ — $ — $ — December 31, 2016 $ 2,022 $ (14 ) $ — $ — $ 2,022 $ (14 ) Our Credit Risk and Non-Agency Securities are subject to risk of loss with regard to principal and interest payments and at December 31, 2017 and December 31, 2016 , have generally either been assigned below investment grade ratings by rating agencies, or have not been rated. We evaluate each investment based on the characteristics of the underlying collateral and securitization structure, rather than relying on the ratings assigned by rating agencies. During the year ended December 31, 2017 and December 31, 2016 , we sold $8,372 and $61,843 of Credit Risk and Non-Agency Securities, which resulted in gains of $85 and $333 . Sales are executed to reposition our MBS portfolio and to reach our target level of liquidity.

Credit Risk and Non-Agency Secu

Credit Risk and Non-Agency Securities, Trading	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Credit Risk and Non-Agency Securities, Trading	Note 6 -Agency Securities, Available for Sale All of our Agency Securities are classified as available for sale and, as such, are reported at their estimated fair value and changes in fair value reported as part of the statements of comprehensive income (loss). At December 31, 2017 and December 31, 2016 , investments in Agency Securities accounted for 88.2% and 85.7% of our MBS portfolio. We evaluated our Agency Securities with unrealized losses at December 31, 2017 , December 31, 2016 and December 31, 2015 , to determine whether there was an other than temporary impairment. All of our Agency Securities are issued and guaranteed by GSEs or Ginnie Mae. The GSEs have a long term credit rating of AA+. At those dates, we also considered whether we intended to sell Agency Securities and whether it was more likely than not that we could meet our liquidity requirements and contractual obligations without selling Agency Securities. Results of this evaluation for the year ended December 31, 2017 : During 2017, we identified certain low yielding Agency Securities that we plan to replace with securities having more attractive returns as market conditions permit. Accordingly, we recognized losses totaling $13,707 in our consolidated financial statements of operations, thereby establishing a new cost basis for those Agency Securities with an aggregate fair value of $795,724 as of December 31, 2017 . We determined that there was no other than temporary impairment of our remaining Agency Securities as of December 31, 2017 Results of this evaluation for the year ended December 31, 2016 : Anticipating portfolio repositioning sales in January 2017, we concluded that the December 31, 2016 unrealized losses on certain of our 3.0% 15 -year fixed rate Agency Securities represented an other than temporary impairment. Accordingly, we recognized losses totaling $6,540 in our consolidated financial statements of operations, thereby establishing a new cost basis for those Agency Securities with an aggregate fair value of $785,285 as of December 31, 2016 . We determined that there was no other than temporary impairment of our remaining Agency Securities as of December 31, 2016 . Results of this evaluation for the year ended December 31, 2015 : No other than temporary impairment was recognized for the year ended December 31, 2015 because we determined that we 1) did not have the intent to sell the Agency Securities in an unrealized loss position, 2) did not believe it more likely than not that we were required to sell the securities before recovery (for example, because of liquidity requirements or contractual obligations), and/or (3) determined that a credit loss did not exist. At December 31, 2017 , we had the following Agency Securities in an unrealized gain or loss position as presented below. The components of the carrying value of our Agency Securities at December 31, 2017 are also presented below. Our Agency Securities had a weighted average coupon of 3.68% at December 31, 2017 . December 31, 2017 Amortized Cost Gross Unrealized Loss Gross Unrealized Gain Fair Value Percent of Total Fannie Mae ARMs & Hybrids $ 28,199 $ (229 ) $ 112 $ 28,082 0.38 % Multi-Family MBS 1,799,737 (5,132 ) 16,950 1,811,555 24.22 10 Year Fixed 60,634 (347 ) 137 60,424 0.81 15 Year Fixed 1,028,797 (4,955 ) 625 1,024,467 13.70 20 Year Fixed 29,832 (621 ) — 29,211 0.39 25 Year Fixed 9,367 (140 ) — 9,227 0.12 30 Year Fixed 2,938,655 (18,910 ) 431 2,920,176 39.05 Total Fannie Mae $ 5,895,221 $ (30,334 ) $ 18,255 $ 5,883,142 78.67 % Freddie Mac 10 Year Fixed 37,254 (158 ) 228 37,324 0.50 15 Year Fixed 354,878 (211 ) 787 355,454 4.75 25 Year Fixed 41,383 (857 ) — 40,526 0.54 30 Year Fixed 1,131,584 (7,300 ) — 1,124,284 15.03 Total Freddie Mac $ 1,565,099 $ (8,526 ) $ 1,015 $ 1,557,588 20.82 % Ginnie Mae ARMs & Hybrids 38,494 (532 ) 4 37,966 0.51 10 Year Fixed 263 — 7 270 0.00 Total Ginnie Mae $ 38,757 $ (532 ) $ 11 $ 38,236 0.51 % Total Agency Securities $ 7,499,077 $ (39,392 ) $ 19,281 $ 7,478,966 100.00 % At December 31, 2016 , we had the following securities in an unrealized gain or loss position as presented below. The components of the carrying value of our Agency Securities at December 31, 2016 are also presented below. Our Agency Securities had a weighted average coupon of 3.52% at December 31, 2016 . December 31, 2016 Amortized Cost Gross Unrealized Loss Gross Unrealized Gain Fair Value Percent of Total Fannie Mae ARMs & Hybrids $ 38,140 $ (174 ) $ 303 $ 38,269 0.60 % Multi-Family MBS 1,439,126 (5,677 ) 8,324 1,441,773 22.14 10 Year Fixed 93,440 (755 ) 335 93,020 1.43 15 Year Fixed 2,796,785 (10,424 ) 2,011 2,788,372 42.82 20 Year Fixed 338,017 (4,629 ) — 333,388 5.12 25 Year Fixed 12,126 (105 ) — 12,021 0.18 30 Year Fixed 1,062,718 (10,902 ) — 1,051,816 16.15 Total Fannie Mae $ 5,780,352 $ (32,666 ) $ 10,973 $ 5,758,659 88.44 % Freddie Mac 10 Year Fixed 48,030 (149 ) 501 48,382 0.75 15 Year Fixed 530,590 (5,876 ) 1,633 526,347 8.08 20 Year Fixed 19,503 (410 ) — 19,093 0.29 25 Year Fixed 115,442 (2,370 ) — 113,072 1.74 Total Freddie Mac $ 713,565 $ (8,805 ) $ 2,134 $ 706,894 10.86 % Ginnie Mae ARMs & Hybrids 46,092 (786 ) 3 45,309 0.70 10 Year Fixed 289 — 13 302 0.00 Total Ginnie Mae $ 46,381 $ (786 ) $ 16 $ 45,611 0.70 % Total Agency Securities $ 6,540,298 $ (42,257 ) $ 13,123 $ 6,511,164 100.00 % Recognition of interest income commences on the settlement date of the purchase transaction and continues through the settlement date of the sale transaction. Actual maturities of Agency Securities are generally shorter than stated contractual maturities because actual maturities of Agency Securities are affected by the contractual lives of the underlying mortgages, periodic payments of principal and prepayments of principal. The following table summarizes the weighted average lives of our Agency Securities at December 31, 2017 and December 31, 2016 . December 31, 2017 December 31, 2016 Weighted Average Life of all Agency Securities Fair Value Amortized Cost Fair Value Amortized Cost Less than one year $ — $ — $ 4 $ 5 Greater than or equal to one year and less than three years 29,126 29,269 17,773 17,998 Greater than or equal to three years and less than five years 1,353,036 1,353,998 3,237,524 3,248,401 Greater than or equal to five years 6,096,804 6,115,810 3,255,863 3,273,894 Total Agency Securities $ 7,478,966 $ 7,499,077 $ 6,511,164 $ 6,540,298 We use a third party model to calculate the weighted average lives of our Agency Securities. Weighted average life is calculated based on expectations for estimated prepayments for the underlying mortgage loans of our Agency Securities. These estimated prepayments are based on assumptions such as interest rates, current and future home prices, housing policy and borrower incentives. The weighted average lives of our Agency Securities at December 31, 2017 and December 31, 2016 in the table above are based upon market factors, assumptions, models and estimates from the third party model and also incorporate management’s judgment and experience. The actual weighted average lives of our Agency Securities could be longer or shorter than estimated. The following table presents the unrealized losses and estimated fair value of our Agency Securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2017 and December 31, 2016 . Unrealized Loss Position For: Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 $ 4,355,924 $ (28,906 ) $ 733,637 $ (10,486 ) $ 5,089,561 $ (39,392 ) December 31, 2016 $ 4,069,170 $ (41,045 ) $ 61,133 $ (1,212 ) $ 4,130,303 $ (42,257 ) During the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 we sold $4,012,398 , $7,195,157 and $5,367,123 of Agency Securities, which resulted in realized losses of $(8,486) , $(18,211) , and $(11,546) , respectively. Sales are executed to reposition our MBS portfolio and to reach our target level of liquidity. Note 7 -Credit Risk and Non-Agency Securities, Trading All of our Credit Risk and Non-Agency Securities are classified as trading securities and reported at their estimated fair value. Fair value changes are reported in the consolidated statements of operations in the period in which they occur. At December 31, 2017 and December 31, 2016 , investments in Credit Risk and Non-Agency Securities accounted for 11.5% and 13.9% of our MBS portfolio. The components of the carrying value of our Credit Risk and Non-Agency Securities at December 31, 2017 are presented in the table below. Credit Risk and Non-Agency Securities December 31, 2017 Fair Value Amortized Cost Principal Amount Weighted Average Coupon Credit Risk Transfer $ 870,494 $ 753,422 $ 764,172 6.05 % Legacy Prime Fixed 16,778 15,287 19,237 6.03 % Legacy ALT-A Fixed 54,727 48,516 65,920 5.85 % Legacy Prime Hybrid 10,469 9,517 11,452 3.17 % Legacy ALT-A Hybrid 4,660 3,895 4,901 3.47 % New Issue Prime Fixed 18,701 17,957 — 19,025 3.69 % Total Credit Risk and Non-Agency Securities $ 975,829 $ 848,594 $ 884,707 5.95 % The components of the carrying value of our Credit Risk and Non-Agency Securities at December 31, 2016 are presented in the table below. Credit Risk and Non-Agency Securities December 31, 2016 Fair Value Amortized Cost Principal Amount Weighted Average Coupon Credit Risk Transfer $ 821,343 $ 764,982 $ 778,216 5.26% NPL/RPL 122,802 121,869 122,561 3.80% Legacy Prime Fixed 19,954 19,406 24,409 6.03% Legacy ALT-A Fixed 59,253 56,776 76,151 5.85% Legacy Prime Hybrid 11,914 11,163 13,641 2.72% Legacy ALT-A Hybrid 6,039 5,669 6,956 3.01% New Issue Prime Fixed 10,865 10,708 11,324 3.66% Total Credit Risk and Non-Agency Securities $ 1,052,170 $ 990,573 $ 1,033,258 5.08% Our Credit Risk Transfer securities are collaterized by residential mortgage loans meeting agency criteria. However, our securities principal and interest are not guaranteed by the agencies. Credit Risk Transfer securities include tranches issued since 2014. Our NPL/RPL securities included tranches issued since 2015 were collaterized by non-performing and re-performing loans. Our Legacy and New Issue Prime Fixed securities are collaterized by residential mortgage loans not guaranteed by any agency. Legacy Prime Fixed, Legacy Alt-A Fixed securities include tranches issued between 2005-2007. New Issue Prime Fixed securities include tranches issued in 2013. The following table summarizes the weighted average lives of our Credit Risk and Non-Agency Securities at December 31, 2017 and December 31, 2016 . December 31, 2017 December 31, 2016 Weighted Average Life of all Credit Risk and Non-Agency Securities Fair Value Amortized Cost Fair Value Amortized Cost Less than one year $ — $ — $ — $ — Greater than or equal to one year and less than three years — — 122,802 121,869 Greater than or equal to three years and less than five years 169,189 149,436 94,839 88,750 Greater than or equal to five years 806,640 699,158 834,529 779,954 Total Credit Risk and Non-Agency Securities $ 975,829 $ 848,594 $ 1,052,170 $ 990,573 We use a third party model to calculate the weighted average lives of our Credit Risk and Non-Agency Securities. Weighted average life is calculated based on expectations for estimated prepayments for the underlying mortgage loans of our Credit Risk and Non-Agency Securities. These estimated prepayments are based on assumptions such as interest rates, current and future home prices, housing policy and borrower incentives. The weighted average lives of our Credit Risk and Non-Agency Securities at December 31, 2017 and December 31, 2016 , in the tables above are based upon market factors, assumptions, models and estimates from the third party model and also incorporate management’s judgment and experience. The actual weighted average lives of our Credit Risk and Non-Agency Securities could be longer or shorter than estimated. The following table presents the unrealized losses and estimated fair value of our Credit Risk and Non-Agency Securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2017 and December 31, 2016 . Unrealized Loss Position For: Less than 12 Months 12 Months or More Total As of Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 $ — $ — $ — $ — $ — $ — December 31, 2016 $ 2,022 $ (14 ) $ — $ — $ 2,022 $ (14 ) Our Credit Risk and Non-Agency Securities are subject to risk of loss with regard to principal and interest payments and at December 31, 2017 and December 31, 2016 , have generally either been assigned below investment grade ratings by rating agencies, or have not been rated. We evaluate each investment based on the characteristics of the underlying collateral and securitization structure, rather than relying on the ratings assigned by rating agencies. During the year ended December 31, 2017 and December 31, 2016 , we sold $8,372 and $61,843 of Credit Risk and Non-Agency Securities, which resulted in gains of $85 and $333 . Sales are executed to reposition our MBS portfolio and to reach our target level of liquidity.

Repurchase Agreements

Repurchase Agreements	12 Months Ended
	Dec. 31, 2017
Disclosure of Repurchase Agreements [Abstract]
Repurchase Agreements	Note 8 -Repurchase Agreements At December 31, 2017 , we had MRAs with 46 counterparties and had $7,555,917 in outstanding borrowings with 32 of those counterparties. At December 31, 2016 , we had MRAs with 42 counterparties and had $6,818,453 in outstanding borrowings with 25 of those counterparties. The following table represents the contractual repricing regarding our repurchase agreements to finance MBS purchases at December 31, 2017 and December 31, 2016 . No amounts below are subject to offsetting. December 31, 2017 Repurchase Agreements Weighted Average Contractual Rate Weighted Average Maturity in days Haircut for Repurchase Agreements (1) Agency Securities $ 6,793,481 1.60 % 55 4.29 % Credit Risk and Non-Agency Securities 762,436 2.67 % 15 21.68 % Total or Weighted Average $ 7,555,917 1.71 % 51 6.39 % (1) The Haircut represents the weighted average margin requirement, or the percentage amount by which the collateral value must exceed the loan amount. December 31, 2016 Repurchase Agreements Weighted Average Contractual Rate Weighted Average Maturity in days Haircut for Repurchase Agreements (1) Agency Securities $ 6,017,843 0.92 % 22 4.70 % Credit Risk and Non-Agency Securities 778,015 2.26 % 23 23.82 % U.S. Treasury Securities 22,595 0.46 % 3 1.11 % Total or Weighted Average $ 6,818,453 1.07 % 22 7.45 % (1) The Haircut represents the weighted average margin requirement, or the percentage amount by which the collateral value must exceed the loan amount. Our repurchase agreements require that we maintain adequate pledged collateral. A decline in the value of the MBS pledged as collateral for borrowings under repurchase agreements could result in the counterparties demanding additional collateral pledges or liquidation of some of the existing collateral to reduce borrowing levels. We manage this risk by maintaining an adequate balance of available cash and unpledged securities. An event of default or termination event under the standard MRA would give our counterparty the option to terminate all repurchase transactions existing with us and require any amount due to be payable immediately. In addition, certain of our MRAs contain a restriction that prohibits our leverage from exceeding twelve times our stockholders’ equity as well as termination events in the case of significant reductions in equity capital. We also may receive cash or securities as collateral from our derivative counterparties which we may use as additional collateral for repurchase agreements. Certain interest rate swap contracts provide for cross collateralization and cross default with repurchase agreements and other contracts with the same counterparty. December 31, 2017 December 31, 2016 Maturing or Repricing Repurchase Agreements Weighted Average Contractual Rate Repurchase Agreements Weighted Average Contractual Rate Within 30 days $ 1,738,768 2.08 % $ 5,082,076 1.11 % 31 days to 60 days 2,394,450 1.59 % 1,699,197 0.94 % 61 days to 90 days 3,422,699 1.61 % 37,180 2.38 % Greater than 90 days — 0.00 % — — % Total or Weighted Average $ 7,555,917 1.71 % $ 6,818,453 1.07 % At December 31, 2017 , Buckler Securities LLC, (See Note 15 -Related Party Transactions ) accounted for 38.4% of our aggregate borrowings and had an amount at risk of 9.0% of our total stockholders' equity with a weighted average maturity of 70 days on repurchase agreements. In addition, at December 31, 2017 , we had 1 repurchase agreement counterparty that individually accounted for between 5% and 10% of our aggregate borrowings. In total, this counterparty accounted for approximately 5.1% of our repurchase agreement borrowings outstanding at December 31, 2017 . At December 31, 2016 , we had 9 repurchase agreement counterparties that individually accounted for between 5% and 10% of our aggregate borrowings. In total, these counterparties accounted for 60.0% of our repurchase agreement borrowings at December 31, 2016 . No counterparty held collateral in excess of 5% of our total stockholders' equity at December 31, 2016 .

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Note 9 -Derivatives We enter into derivative transactions to manage our interest rate risk exposure. These transactions may include entering into interest rate swap contracts, swaptions and basis swaps. These transactions are designed to lock in funding costs for repurchase agreements associated with our assets in such a way to help assure the realization of net interest margins. Such transactions are based on assumptions about prepayments which, if not realized, will cause transaction results to differ from expectations. Basis swap contracts allow us to exchange one floating interest rate basis for another, for example, 3 month LIBOR and Fed Funds Rates, thereby allowing us to diversify our floating rate basis exposures. We also utilize forward contracts for the purchase or sale of TBA Agency Securities. We have agreements with our derivative counterparties that provide for the posting of collateral based on the fair values of our interest rate swap contracts, swaptions, basis swap contracts and TBA Agency Securities. Through this margin process, either we or our swap counterparty may be required to pledge cash or Agency Securities as collateral. Collateral requirements vary by counterparty and change over time based on the fair value, notional amount and remaining term of the contracts. Certain interest rate swap contracts provide for cross collateralization and cross default with repurchase agreements and other contracts with the same counterparty. Interest rate swaptions generally provide us the option to enter into an interest rate swap agreement at a certain point of time in the future with a predetermined notional amount, stated term and stated rate of interest in the fixed leg and interest rate index on the floating leg. TBA Agency Securities are forward contracts for the purchase (“long position”) or sale (“short position”) of Agency Securities at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific Agency Securities delivered into the contract upon the settlement date, published each month by the Securities Industry and Financial Markets Association, are not known at the time of the transaction. We may enter into TBA Agency Securities as a means of hedging against short-term changes in interest rates. We may also enter into TBA Agency Securities as a means of acquiring or disposing of Agency Securities and we may from time to time utilize TBA dollar roll transactions to finance Agency Security purchases. We estimate the fair value of TBA Agency Securities based on similar methods used to value our Agency Securities. The following tables present information about our derivatives at December 31, 2017 and December 31, 2016 . December 31, 2017 Derivative Type Remaining / Underlying Term Weighted Average Remaining Swap / Option Term (Months) Weighted Average Rate Notional Amount Asset Fair Value (1) Liability Fair Value (1) Interest rate swap contracts 0-12 Months 5 0.92 % $ 50,000 $ 191 $ — Interest rate swap contracts 13-24 Months 23 1.21 % 550,000 6,398 — Interest rate swap contracts 25-36 Months 30 1.48 % 675,000 5,495 — Interest rate swap contracts 61-72 Months 65 1.97 % 1,975,000 11,624 (250 ) Interest rate swap contracts 73-84 Months 79 1.89 % 575,000 3,306 (1,885 ) Interest rate swap contracts 97-108 Months 107 1.93 % 1,050,000 9,263 (10 ) Interest rate swap contracts 109-120 Months 114 2.10 % 375,000 — (3,545 ) TBA Agency Securities (2) 0-60 Months n/a n/a 1,600,000 934 (2,258 ) Total or Weighted Average $ 6,850,000 $ 37,211 $ (7,948 ) (1) See Note 5 , “ Fair Value of Financial Instruments ” for additional discussion. (2) Implied cost basis of $1,674,438 and implied market value of $1,673,113 . December 31, 2016 Derivative Type Remaining / Underlying Term Weighted Average Remaining Swap / Option Term (Months) Weighted Average Rate Notional Amount (3) Asset Fair Value (1) Liability Fair Value (1) Interest rate swap contracts 0-12 Months 7 0.54 % $ 200,000 $ 158 $ — Interest rate swap contracts 13-24 Months 17 0.92 % 50,000 — (117 ) Interest rate swap contracts 25-36 Months 35 1.21 % 550,000 1,547 — Interest rate swap contracts 73-84 Months 77 1.97 % 2,075,000 3,690 (10,767 ) Interest rate swap contracts 85-96 Months 84 1.97 % 100,000 — (1,242 ) Interest rate swap contracts 109-120 Months 119 1.95 % 1,250,000 2,378 (2,278 ) TBA Agency Securities (2) 0-60 Months n/a n/a 2,850,000 2,064 (35,251 ) Total or Weighted Average $ 7,075,000 $ 9,837 $ (49,655 ) (1) See Note 5, “Fair Value of Financial Instruments” for additional discussion. (2) Implied cost basis of $2,922,582 and implied market value of $2,889,395 . (3) Notional amount includes $300,000 of forward starting interest rate swap contracts which became effective on January 3, 2017. We have netting arrangements in place with all derivative counterparties pursuant to standard documentation developed by the International Swap and Derivatives Association. We are also required to post or hold cash collateral based upon the net underlying market value of our open positions with the counterparty. The following tables present information about interest rate swap contracts and Agency Securities TBA and the potential effects of netting if we were to offset the assets and liabilities of these financial instruments on the accompanying consolidated balance sheets. Currently, we present these financial instruments at their gross amounts and they are included in derivatives, at fair value on the accompanying consolidated balance sheet at December 31, 2017 . December 31, 2017 Gross Amounts Not Offset in the Consolidated Balance Sheet Assets Gross and Net Amounts of Assets Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ 36,277 $ (5,690 ) $ (22,689 ) $ 7,898 Agency Securities TBA 934 (2,258 ) 8,068 6,744 Totals $ 37,211 $ (7,948 ) $ (14,621 ) $ 14,642 December 31, 2017 Gross Amounts Not Offset in the Consolidated Balance Sheet Liabilities Gross and Net Amounts of Liabilities Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ (5,690 ) $ 5,690 $ — $ — Agency Securities TBA (2,258 ) 2,258 — — Totals $ (7,948 ) $ 7,948 $ — $ — The following tables present information about interest rate swap contracts and Agency Securities TBA and the potential effects of netting if we were to offset the assets and liabilities of these financial instruments on the accompanying consolidated balance sheets. Currently, we present these financial instruments at their gross amounts and they are included in derivatives, at fair value on the accompanying consolidated balance sheet at December 31, 2016 . December 31, 2016 Gross Amounts Not Offset in the Consolidated Balance Sheet Assets Gross and Net Amounts of Assets Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ 7,773 $ (14,404 ) $ 19,395 $ 12,764 Agency Securities TBA 2,064 (35,251 ) 37,839 4,652 Totals $ 9,837 $ (49,655 ) $ 57,234 $ 17,416 December 31, 2016 Gross Amounts Not Offset in the Consolidated Balance Sheet Liabilities Gross and Net Amounts of Liabilities Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ (14,404 ) $ 14,404 $ — $ — Agency Securities TBA (35,251 ) 35,251 — — Totals $ (49,655 ) $ 49,655 $ — $ — The following table represents the location and information regarding our derivatives which are included in Other Income (Loss) in the accompanying consolidated statements of operations for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . Income (Loss) Recognized For the Year Ended Derivatives Location on consolidated statements of operations December 31, 2017 December 31, 2016 December 31, 2015 Interest rate swap contracts: Realized gain (loss) Realized loss on derivatives $ 990 $ (370,192 ) $ (2,274 ) Interest income Realized loss on derivatives 50,464 25,270 13,066 Interest expense Realized loss on derivatives (83,797 ) (90,978 ) (123,929 ) Changes in fair value Unrealized gain (loss) on derivatives 39,388 208,082 (182,503 ) $ 7,045 $ (227,818 ) $ (295,640 ) Futures Contracts: Realized loss Realized loss on derivatives — — (184 ) Changes in fair value Unrealized gain (loss) on derivatives — — 180 $ — $ — $ (4 ) Basis swap contracts: Realized gain Realized loss on derivatives — 1,468 — Interest income Realized loss on derivatives — 2,617 803 Interest expense Realized loss on derivatives — (3,116 ) (922 ) Changes in fair value Unrealized gain (loss) on derivatives — (661 ) 661 $ — $ 308 $ 542 TBA Agency Securities: Realized gain (loss) Realized loss on derivatives 9,668 (17,467 ) 6,370 Changes in fair value Unrealized gain (loss) on derivatives (116 ) (1,209 ) — $ 9,552 $ (18,676 ) $ 6,370 Totals $ 16,597 $ (246,186 ) $ (288,732 )

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 10 -Commitments and Contingencies Management Agreements with ACM The Company is managed by ACM, pursuant to management agreements with ARMOUR and JAVELIN (see also Note 15 , “ Related Party Transactions ” ) . The management agreements entitle ACM to receive a management fee payable monthly in arrears. Currently, the monthly ARMOUR management fee is 1/12th of the sum of (a) 1.5% of gross equity raised up to $1.0 billion plus (b) 0.75% of gross equity raised in excess of $1.0 billion . The cost of repurchased stock and any dividend representing a return of capital for tax purposes will reduce the amount of gross equity raised used to calculate the monthly management fee. In connection with the acquisition of JAVELIN, we included in accounts payable and other accrued expenses in our consolidated statements of operations a liability which was recognized as the fair value of JAVELIN’s management agreement with ACM, see Note 16 -Acquisition of JAVELIN Mortgage Investment Corp. At December 31, 2017 , December 31, 2016 and December 31, 2015 , the effective ARMOUR management fee was 1.04% , 1.05% and 1.05% based on gross equity raised of $2,618,020 , $2,469,368 and $2,507,505 , respectively. The ACM monthly management fees are not calculated based on the performance of our assets. Accordingly, the payment of our monthly management fees may not decline in the event of a decline in our earnings and may cause us to incur losses. We are also responsible for any costs and expenses that ACM incurred solely on behalf of ARMOUR or JAVELIN other than the various overhead expenses specified in the terms of the management agreements. ACM is further entitled to receive termination fees from ARMOUR and JAVELIN under certain circumstances. Indemnifications and Litigation We enter into certain contracts that contain a variety of indemnifications, principally with ACM and underwriters, against third party claims for errors and omissions in connection with their services to us. We have not incurred any costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, the estimated fair value of these agreements, as well as the maximum amount attributable to past events, is not material. Accordingly, we have no liabilities recorded for these agreements at December 31, 2017 and December 31, 2016 . Nine putative class action lawsuits have been filed in connection with the tender offer (the “Tender Offer”) and merger (the “Merger”) for JAVELIN ( Note 16 -Acquisition of JAVELIN Mortgage Investment Corp. for more information about the Tender Offer and Merger). The Tender Offer and Merger are collectively defined herein as the “Transactions.” All nine suits name ARMOUR, the previous members of JAVELIN’s board of directors prior to the Merger (of which eight are current members of ARMOUR’s board of directors) (the “Individual Defendants”) and JMI Acquisition Corporation (“Acquisition” ) as defendants.Certain cases also name ACM and JAVELIN as additional defendants. The lawsuits were brought by purported holders of JAVELIN’s common stock, both individually and on behalf of a putative class of JAVELIN’s stockholders, alleging that the Individual Defendants breached their fiduciary duties owed to the plaintiffs and the putative class of JAVELIN stockholders, including claims that the Individual Defendants failed to properly value JAVELIN; failed to take steps to maximize the value of JAVELIN to its stockholders; ignored or failed to protect against conflicts of interest; failed to disclose material information about the Transactions; took steps to avoid competitive bidding and to give ARMOUR an unfair advantage by failing to adequately solicit other potential acquirors or alternative transactions; and erected unreasonable barriers to other third-party bidders. The suits also allege that ARMOUR, JAVELIN, ACM and Acquisition aided and abetted the alleged breaches of fiduciary duties by the Individual Defendants. The lawsuits seek equitable relief, including, among other relief, to enjoin consummation of the Transactions, or rescind or unwind the Transactions if already consummated, and award costs and disbursements, including reasonable attorneys’ fees and expenses. The sole Florida lawsuit was never served on the defendants, and that case was voluntarily dismissed and closed on January 20, 2017 . On April 25, 2016, the Maryland court issued an order consolidating the eight Maryland cases into one action, captioned In re JAVELIN Mortgage Investment Corp. Shareholder Litigation (Case No. 24-C-16-001542), and designated counsel for one of the Maryland cases as interim lead co-counsel. On May 26, 2016, interim lead counsel filed the Consolidated Amended Class Action Complaint for Breach of Fiduciary Duty asserting consolidated claims of breach of fiduciary duty, aiding and abetting the breaches of fiduciary duty, and waste. On June 27, 2016, defendants filed a Motion to Dismiss the Consolidated Amended Class Action Complaint for failing to state a claim upon which relief can be granted. A hearing was held on the Motion to Dismiss on March 3, 2017, and the Court reserved ruling. To date, the Court has not issued an order on the Motion to Dismiss. Each of ARMOUR, JAVELIN, ACM and the Individual Defendants intends to defend the claims made in these lawsuits vigorously; however, there can be no assurance that any of ARMOUR, JAVELIN, ACM or the Individual Defendants will prevail in its defense of any of these lawsuits to which it is a party. An unfavorable resolution of any such litigation surrounding the Transactions may result in monetary damages being awarded to the plaintiffs and the putative class of former stockholders of JAVELIN and the cost of defending the litigation, even if resolved favorably, could be substantial. Due to the preliminary nature all of these suits, ARMOUR is not able at this time to estimate their outcome.

Stock Based Compensation

Stock Based Compensation	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Based Compensation	Note 11 -Stock Based Compensation We adopted the 2009 Stock Incentive Plan as amended, (the “Plan”) to attract, retain and reward directors and other persons who provide services to us in the course of operations. The Plan authorizes the Board to grant awards including common stock, restricted shares of common stock (“RSUs”), stock options, performance shares, performance units, stock appreciation rights and other equity and cash-based awards (collectively “Awards”), subject to terms as provided in the Plan. On May 8, 2014, our stockholders approved an amendment to the Plan to increase the number of shares issuable thereunder from 2,000 to 15,000 shares and the Plan was amended accordingly. In connection with the Reverse Stock Split which was effective July 31, 2015, the number of shares of common stock issuable under the Plan was properly adjusted to 1,875 shares. In November 2017, we elected to make restricted stock unit awards to ACM and to the Board totaling 472 shares. These awards begin vesting in February 2018. Transactions related to awards for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 are summarized below: December 31, 2017 December 31, 2016 December 31, 2015 Number of Awards Weighted Average Grant Date Fair Value per Award Number of Awards Weighted Average Grant Date Fair Value per Award Number of Awards Weighted Average Grant Date Fair Value per Award Unvested RSU Awards Outstanding beginning of period 32 $ 39.80 78 $ 48.85 132 $ 51.76 Granted 472 $ 24.82 — $ — — $ — Vested (32 ) $ 39.80 (46 ) $ 56.14 (53 ) $ 56.40 Forfeited — $ — — $ — (1 ) $ 58.90 Unvested RSU Awards Outstanding end of period 472 $ 24.82 32 $ 39.80 78 $ 48.85 At December 31, 2017 , there was approximately $12,063 of unvested stock based compensation related to the Awards (based on a stock price of $25.56 per share), that we expect to recognize as an expense over the remaining average service period of 3.6 years . Our policy is to account for forfeitures as they occur. We also pay our non-executive Board quarterly fees of $33 , which is payable in cash, common stock, or a combination of common stock and cash at the option of the director.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Stockholders' Equity	Note 12 -Stockholders' Equity Preferred Stock At December 31, 2017 and December 31, 2016 , we were authorized to issue up to 50,000 shares of preferred stock, par value $0.001 per share, with such designations, voting and other rights and preferences as may be determined from time to time by our Board of Directors (“Board”) or a committee thereof. We have designated 9,610 shares as 8.250% Series A Preferred Stock and 7,650 shares as 7.875% Series B Preferred Stock. At December 31, 2017 , a total of 32,740 shares of our authorized preferred stock remain available for designation as future series. Series A Cumulative Preferred Shares (“Series A Preferred Stock”) At December 31, 2017 and December 31, 2016 , we had 2,181 shares of Series A Preferred Stock issued and outstanding with a par value of $0.001 per share and a liquidation preference of $25.00 per share, or $54,514 in the aggregate. Shares designated as Series A Preferred Stock but unissued totaled 7,429 at December 31, 2017 . At December 31, 2017 and December 31, 2016 , there were no accrued or unpaid dividends on the Series A Preferred Stock. The Series A Preferred Stock is entitled to a dividend at a rate of 8.250% per year based on the $25.00 per share liquidation preference before the common stock is entitled to receive any dividends. The Series A Preferred Stock is redeemable at $25.00 per share plus accrued and unpaid dividends exclusively at our option commencing on June 7, 2017 (subject to our right under limited circumstances to redeem the Series A Preferred Stock earlier in order to preserve our qualification as a REIT). The Series A Preferred Stock is senior to our common stock and therefore in the event of liquidation, dissolution or winding up, the Series A Preferred Stock will receive a liquidation preference of $25.00 per share plus accumulated and unpaid dividends before distributions are paid to holders of our common stock, with no right or claim to any of our remaining assets thereafter. The Series A Preferred Stock generally does not have voting rights, except if we fail to pay dividends on the Series A Preferred Stock for eighteen months, whether or not consecutive. Under such circumstances, the Series A Preferred Stock will be entitled to vote to elect two additional directors to the Board, until all unpaid dividends have been paid or declared and set aside for payment. The Series A Preferred Stock has no stated maturity, is not subject to any sinking fund or mandatory redemption and will remain outstanding indefinitely unless repurchased or redeemed by us or converted into our common stock in connection with a change of control by the holders of Series A Preferred Stock. Series B Cumulative Preferred Shares (“Series B Preferred Stock”) At December 31, 2017 and December 31, 2016 , we had 6,262 and 5,650 shares of Series B Preferred Stock, respectively, issued and outstanding with a par value of $0.001 per share and a liquidation preference of $25.00 per share, or $156,560 and $141,250 , respectively, in the aggregate. Shares designated as Series B Preferred Stock but unissued totaled 1,388 at December 31, 2017 . At December 31, 2017 and December 31, 2016 , there were no accrued or unpaid dividends on the Series B Preferred Stock. The Series B Preferred Stock is entitled to a dividend at a rate of 7.875% per year based on the $25.00 per share liquidation preference before the common stock is entitled to receive any dividends. The Series B Preferred Stock is redeemable at $25.00 per share plus accrued and unpaid dividends exclusively at our option commencing on February 12, 2018 (subject to our right under limited circumstances to redeem the Series A Preferred Stock earlier in order to preserve our qualification as a REIT). The Series B Preferred Stock is senior to our common stock and rank on parity with the Series A Preferred Stock. In the event of liquidation, dissolution or winding up, the Series B Preferred Stock will receive a liquidation preference of $25.00 per share plus accumulated and unpaid dividends before distributions are paid to holders of our common stock, with no right or claim to any of our remaining assets thereafter. The Series B Preferred Stock generally does not have voting rights, except if we fail to pay dividends on the Series B Preferred Stock for eighteen months, whether or not consecutive. Under such circumstances, the Series B Preferred Stock will be entitled to vote to elect two additional directors to the Board, until all unpaid dividends have been paid or declared and set aside for payment. The Series B Preferred Stock has no stated maturity, is not subject to any sinking fund or mandatory redemption and will remain outstanding indefinitely unless repurchased or redeemed by us or converted into our common stock in connection with a change of control by the holders of Series B Preferred Stock. On August 30, 2017, the Company entered into an ATM Equity Offering Sales Agreement (the “Preferred B ATM Sales Agreement”) relating to an "at-the-market" offering program for our Series B Preferred Stock. In accordance with the terms of the Preferred B ATM Sales Agreement, we may offer and sell over a period of time and from time to time, up to 2,000 shares of our Series B Preferred Stock. See below tables for Series B Preferred Stock equity raising activities. Common Stock Common Stock At December 31, 2017 and December 31, 2016 , we were authorized to issue up to 125,000 shares of common stock, par value $0.001 per share, with such designations, voting and other rights and preferences as may be determined from time to time by our Board. We had 41,877 shares of common stock issued and outstanding at December 31, 2017 and 36,723 shares of common stock issued and outstanding at December 31, 2016 . On May 26, 2017, the Company entered into an ATM Equity Offering Sales Agreement (the “Common stock ATM Sales Agreement”) relating to the shares of our common stock. On October 2, 2017, the Sales Agreement was amended to, among other things, add Ladenburg Thalmann & Co. Inc. as a party to the Sales Agreement. In accordance with the terms of the Common stock ATM Sales Agreement, we may offer and sell over a period of time and from time to time through Merrill Lynch, Pierce, Fenner & Smith Incorporated and/or Ladenburg Thalmann & Co. Inc., as our designated agent or agents, up to 5,000 shares of our common stock par value $0.001 per share. The Common stock ATM Sales Agreement relates to a proposed "at-the-market" offering program. As of December 31, 2017 , we have not sold any shares under this agreement. See below tables for common stock equity raising activities. Common Stock Repurchased At December 31, 2017 and December 31, 2016 , there were 1,874 authorized shares remaining under our common stock repurchase program (the “Repurchase Program”). For the years ended December 31, 2017 and December 31, 2016 , we did not repurchase any common shares under the Repurchase Program. See the below table for common stock repurchases for the year ended December 31, 2015 . Under the Repurchase Program, shares may be purchased in the open market, including block trades, through privately negotiated transactions, or pursuant to a trading plan separately adopted in the future. The timing, manner, price and amount of any repurchases will be at our discretion, subject to the requirements of the Securities Exchange Act of 1934, as amended, and related rules. We are not required to repurchase any shares under the Repurchase Program and it may be modified, suspended or terminated at any time for any reason. We do not intend to purchase shares from our Board or other affiliates. Under Maryland law, such repurchased shares are treated as authorized but unissued. The following table presents our common stock repurchases for the year ended December 31, 2015 . During the years ended December 31, 2017 and December 31, 2016 , we did not repurchase any shares of our common stock. December 31, 2015 Transaction Type Completion Date Number of Per Share price (1) Net Cost Repurchased common shares March 5, 2015-December 31, 2015 7,510 $ 21.25 $ 159,600 (1) Weighted average price Equity Capital Raising Activities The following tables present our equity transactions for the years ended December 31, 2017 and December 31, 2015 . We did not have equity raising transactions for the year ended December 31, 2016 . December 31, 2017 Transaction Type Completion Date Number of Shares Per Share price (1) Net Proceeds Series B Preferred ATM Sales Agreement August 31, 2017-December 30, 2017 612 $ 24.44 $ 14,968 Common stock follow-on public offering June 30, 2017 4,500 $ 25.96 $ 116,693 Common stock dividend reinvestment program September 12, 2017-October 6, 2017 619 $ 26.44 $ 16,500 (1) Weighted average price December 31, 2015 Transaction Type Completion Date Number of Shares Per Share price (1) Net Proceeds Common stock dividend reinvestment program January 26, 2015-November 27, 2015 6 $ 23.21 $ 147 (1) Weighted average price Dividends The following tables present our common stock dividend transactions for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . December 31, 2017 Record Date Payment Date Rate per common share Aggregate amount paid to holders of record January 17, 2017 January 30, 2017 $ 0.19 $ 6,984 February 15, 2017 February 27, 2017 $ 0.19 6,984 March 15, 2017 March 30, 2017 $ 0.19 6,983 April 17, 2017 April 28, 2017 $ 0.19 6,984 May 15, 2017 May 30, 2017 $ 0.19 6,984 June 15, 2017 June 29, 2017 $ 0.19 6,983 July 17, 2017 July 27, 2017 $ 0.19 7,839 August 15, 2017 August 28, 2017 $ 0.19 7,839 September 15, 2017 September 28, 2017 $ 0.19 7,870 October 16, 2017 October 27, 2017 $ 0.19 7,956 November 15, 2017 November 27, 2017 $ 0.19 7,957 December 15, 2017 December 28, 2017 $ 0.19 8,046 Total dividends paid $ 89,409 December 31, 2016 Record Date Payment Date Rate per common share Aggregate amount paid to holders of record January 15, 2016 January 27, 2016 $ 0.33 $ 12,131 February 13, 2016 February 26, 2016 $ 0.33 12,131 March 13, 2016 March 28, 2016 $ 0.33 12,131 April 15, 2016 April 27, 2016 $ 0.27 9,925 May 16, 2016 May 27, 2016 $ 0.22 8,087 June 15, 2016 June 29, 2016 $ 0.22 8,087 July 15, 2016 July 27, 2016 $ 0.22 8,087 August 15, 2016 August 29, 2016 $ 0.22 8,087 September 15, 2016 September 27, 2016 $ 0.22 8,087 October 14, 2016 October 27, 2016 $ 0.22 8,086 November 15, 2016 November 29, 2016 $ 0.22 8,086 December 16, 2016 December 27, 2016 $ 0.22 8,086 Total dividends paid $ 111,011 December 31, 2015 Record Date Payment Date Rate per common share Aggregate amount paid to holders of record January 15, 2015 January 27, 2015 $ 0.32 $ 14,168 February 13, 2015 February 27, 2015 $ 0.32 14,169 March 13, 2015 March 27, 2015 $ 0.32 14,149 April 15, 2015 April 27, 2015 $ 0.32 14,133 May 15, 2015 May 27, 2015 $ 0.32 14,089 June 15, 2015 June 29, 2015 $ 0.32 14,045 July 15, 2015 July 27, 2015 $ 0.32 14,045 August 17, 2015 August 27, 2015 $ 0.33 14,477 September 15, 2015 September 28, 2015 $ 0.33 14,394 October 15, 2015 October 27, 2015 $ 0.33 13,438 November 16, 2015 November 27, 2015 $ 0.33 13,176 December 16, 2015 December 30, 2015 $ 0.33 12,859 Total dividends paid $ 167,142 The following tables present our Series A Preferred Stock dividend transactions for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . December 31, 2017 Record Date Payment Date Rate per Series A Preferred Share Aggregate amount paid to holders of record January 15, 2017 January 27, 2017 $ 0.17 $ 374.8 February 15, 2017 February 27, 2017 $ 0.17 374.8 March 15, 2017 March 27, 2017 $ 0.17 374.8 April 15, 2017 April 27, 2017 $ 0.17 374.8 May 15, 2017 May 30, 2017 $ 0.17 374.8 June 15, 2017 June 27, 2017 $ 0.17 374.8 July 15, 2017 July 27, 2017 $ 0.17 374.8 August 15, 2017 August 28, 2017 $ 0.17 374.8 September 15, 2017 September 27, 2017 $ 0.17 374.8 October 15, 2017 October 27, 2017 $ 0.17 374.8 November 15, 2017 November 27, 2017 $ 0.17 374.8 December 15, 2017 December 27, 2017 $ 0.17 374.8 Total dividends paid $ 4,497.6 December 31, 2016 Record Date Payment Date Rate per Series A Preferred Share Aggregate amount paid to holders of record January 15, 2016 January 27, 2016 $ 0.17 $ 374.8 February 15, 2016 February 26, 2016 $ 0.17 374.8 March 15, 2016 March 28, 2016 $ 0.17 374.8 April 15, 2016 April 27, 2016 $ 0.17 374.8 May 15, 2016 May 27, 2016 $ 0.17 374.8 June 15, 2016 June 29, 2016 $ 0.17 374.8 July 15, 2016 July 27, 2016 $ 0.17 374.8 August 15, 2016 August 29, 2016 $ 0.17 374.8 September 15, 2016 September 27, 2016 $ 0.17 374.8 October 15, 2016 October 27, 2016 $ 0.17 374.8 November 15, 2016 November 27, 2016 $ 0.17 374.8 December 15, 2016 December 28, 2016 $ 0.17 374.8 Total dividends paid $ 4,497.6 December 31, 2015 Record Date Payment Date Rate per Series A Preferred Share Aggregate amount paid to holders of record January 15, 2015 January 27, 2015 $ 0.17 $ 374.8 February 15, 2015 February 27, 2015 $ 0.17 374.8 March 15, 2015 March 27, 2015 $ 0.17 374.8 April 15, 2015 April 27, 2015 $ 0.17 374.8 May 15, 2015 May 27, 2015 $ 0.17 374.8 June 15, 2015 June 29, 2015 $ 0.17 374.8 July 15, 2015 July 27, 2015 $ 0.17 374.8 August 15, 2015 August 27, 2015 $ 0.17 374.8 September 15, 2015 September 28, 2015 $ 0.17 374.8 October 15, 2015 October 27, 2015 $ 0.17 374.8 November 15, 2015 November 27, 2015 $ 0.17 374.8 December 15, 2015 December 28, 2015 $ 0.17 374.8 Total dividends paid $ 4,497.6 The following tables present our Series B Preferred Stock dividend transactions for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . December 31, 2017 Record Date Payment Date Rate per Series B Preferred Share Aggregate amount paid to holders of record January 15, 2017 January 27, 2017 $ 0.16 $ 927 February 15, 2017 February 27, 2017 $ 0.16 927 March 15, 2017 March 27, 2017 $ 0.16 927 April 15, 2017 April 27, 2017 $ 0.16 927 May 15, 2017 May 30, 2017 $ 0.16 927 June 15, 2017 June 27, 2017 $ 0.16 927 July 15, 2017 July 27, 2017 $ 0.16 927 August 15, 2017 August 28, 2017 $ 0.16 927 September 15, 2017 September 27, 2017 $ 0.16 962 October 15, 2017 October 27, 2017 $ 0.16 987 November 15, 2017 November 27, 2017 $ 0.16 998 December 15, 2017 December 27, 2017 $ 0.16 1,019 Total dividends paid $ 11,382 December 31, 2016 Record Date Payment Date Rate per Series B Preferred Share Aggregate amount paid to holders of record January 15, 2016 January 27, 2016 $ 0.16 $ 927 February 15, 2016 February 26, 2016 $ 0.16 927 March 15, 2016 March 28, 2016 $ 0.16 927 April 15, 2016 April 27, 2016 $ 0.16 927 May 15, 2016 May 27, 2016 $ 0.16 927 June 15, 2016 June 29, 2016 $ 0.16 927 July 15, 2016 July 27, 2016 $ 0.16 927 August 15, 2016 August 29, 2016 $ 0.16 927 September 15, 2016 September 27, 2016 $ 0.16 927 October 15, 2016 October 27, 2006 $ 0.16 927 November 15, 2016 November 27, 2016 $ 0.16 927 December 15, 2016 December 28, 2016 $ 0.16 927 Total dividends paid $ 11,124 December 31, 2015 Record Date Payment Date Rate per Series B Preferred Share Aggregate amount paid to holders of record January 15, 2015 January 27, 2015 $ 0.16 $ 927 February 15, 2015 February 27, 2015 $ 0.16 927 March 15, 2015 March 27, 2015 $ 0.16 927 April 15, 2015 April 27, 2015 $ 0.16 927 May 15, 2015 May 27, 2015 $ 0.16 927 June 15, 2015 June 29, 2015 $ 0.16 927 July 15, 2015 July 27, 2015 $ 0.16 927 August 15, 2015 August 27, 2015 $ 0.16 927 September 15, 2015 September 28, 2015 $ 0.16 927 October 15, 2015 October 27, 2015 $ 0.16 927 November 15, 2015 November 27, 2015 $ 0.16 927 December 15, 2015 December 28, 2015 $ 0.16 927 Total dividends paid $ 11,124

Net Income (Loss) per Common Sh

Net Income (Loss) per Common Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Net Income (Loss) per Common Share	Note 13 -Net Income (Loss) per Common Share The following table presents a reconciliation of net income (loss) and the shares used in calculating weighted average basic and diluted earnings per common share for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . For the Years Ended December 31, 2017 December 31, 2016 December 31, 2015 Net Income (Loss) $ 181,154 $ (45,517 ) $ (31,205 ) Less: Preferred dividends (15,880 ) (15,622 ) (15,622 ) Net Income (Loss) available (related) to common stockholders $ 165,274 $ (61,139 ) $ (46,827 ) Weighted average common shares outstanding – basic 39,170 36,698 42,780 Add: Effect of dilutive non-vested awards, assumed vested 472 — — Weighted average common shares outstanding – diluted 39,642 36,698 42,780

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Note 14 -Income Taxes The following table reconciles our GAAP net income (loss) to estimated REIT taxable income for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . For the Years Ended December 31, 2017 December 31, 2016 December 31, 2015 GAAP net income (loss) $ 181,154 $ (45,517 ) $ (31,205 ) Book to tax differences: Credit Risk and Non-Agency Securities (68,505 ) (60,914 ) — Interest-Only Securities 1,216 (7,818 ) — Changes in interest rate contracts (49,930 ) 179,979 177,565 Losses on Security Sales 8,486 18,211 11,546 Other than temporary loss on Agency Securities 13,707 6,540 — Amortization of deferred hedging costs (59,930 ) (47,952 ) (13,731 ) Premium amortization expense on Agency Securities (468 ) — — Bargain purchase price on acquisition of JAVELIN — (6,484 ) — Other 15 19 17 Estimated taxable income $ 25,745 $ 36,064 $ 144,192 Interest rate contracts are treated as hedging transactions for tax purposes. Unrealized gains and losses on open interest rate contracts are not included in the determination of REIT taxable income. Realized gains and losses on interest rate contracts terminated before their maturity are deferred and amortized over the remainder of the original term of the contract for REIT taxable income. Net capital losses realized Amount Available to offset capital gains though 2013 (579,322 ) 2018 2014 (341,850 ) 2019 2015 (5,182 ) 2020 2016 (31,204 ) 2021 The aggregate tax basis of our assets and liabilities was greater than our total Stockholders’ Equity at December 31, 2017 by approximately $69,175 , or approximately $1.65 per common share (based on the 41,877 common shares then outstanding). We are required and intend to timely distribute substantially all of our REIT taxable income in order to maintain our REIT status under the Code. Total dividend payments to stockholders were $105,289 , $126,633 and $182,764 for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 , respectively. Our estimated REIT taxable income available for distribution as dividends was $25,745 , $36,064 and $144,192 for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 , respectively. Our REIT taxable income and dividend requirements to maintain our REIT status are determined on an annual basis. Dividends paid in excess of REIT taxable income for the year (including amounts carried forward from prior years) will generally not be taxable to common stockholders. The portion of the dividends on our common stock which represented non-taxable return of capital was approximately 88.95% in 2017, 81.55% in 2016 and 22.88% in 2015. Our management is responsible for determining whether tax positions taken by us are more likely than not to be sustained on their merits. We have no material unrecognized tax benefits or material uncertain tax positions.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2017
Related Party Transactions [Abstract]
Related Party Transactions	Note 15 -Related Party Transactions ACM The Company is managed by ACM pursuant to management agreements with ARMOUR and JAVELIN. All of our executive officers are also employees of ACM. ACM manages our day-to-day operations, subject to the direction and oversight of the Board. The ARMOUR management agreement runs through June 18, 2024 and is thereafter automatically renewed for an additional five -year term unless terminated under certain circumstances. The JAVELIN Management Agreement renewed on October 5, 2017, for a one -year period, with the base management fee thereunder reduced to one dollar for the entirely of the renewal term. It will be automatically renewed annually for successive one -year terms unless terminated under certain circumstances. Either party must provide 180 days prior written notice of any such termination. Under the terms of the management agreements, ACM is responsible for costs incident to the performance of its duties, such as compensation of its employees and various overhead expenses. ACM is responsible for the following primary roles: • Advising us with respect to, arranging for and managing the acquisition, financing, management and disposition of, elements of our investment portfolio; • Evaluating the duration risk and prepayment risk within the investment portfolio and arranging borrowing and hedging strategies; • Coordinating capital raising activities; • Advising us on the formulation and implementation of operating strategies and policies, arranging for the acquisition of assets, monitoring the performance of those assets and providing administrative and managerial services in connection with our day-to-day operations; and • Providing executive and administrative personnel, office space and other appropriate services required in rendering management services to us. In accordance with the management agreements, we incurred $26,582 , $26,070 and $27,292 in management fees for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . In accordance with the JAVELIN management agreement, we paid management fees of $1,718 and $1,657 for the years ended December 31, 2017 and December 31, 2016 , reducing the liability recorded upon acquisition to zero at December 31, 2017 . We are required to take actions as may be reasonably required to permit and enable ACM to carry out its duties and obligations. We are also responsible for any costs and expenses that ACM incurred solely on our behalf other than the various overhead expenses specified in the terms of the management agreements. For the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 we reimbursed ACM $764 , $1,950 and $1,921 , respectively for other expenses incurred on our behalf. In consideration of our 2012 results, in 2013, we also elected to make a restricted stock units award to our executive officers and other ACM employees through ACM. The award fully vested in December 2017 and resulted in our recognizing stock based compensation expense of $339 , $470 and $623 for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . In November 2017, we elected to make restricted stock unit awards to ACM and to the Board. These awards begin vesting in February 2018. BUCKLER In March 2017, we contributed $352 for a 10% ownership interest in BUCKLER Securities, LLC, (“BUCKLER”) a Delaware limited liability company and a FINRA-regulated broker-dealer, controlled by ACM and certain executive officers of ARMOUR. The investment was included in prepaid and other assets in our consolidated balance sheet and is accounted for using the equity method as BUCKLER maintains specific ownership accounts. The value of the investment was $84 at December 31, 2017 reflecting our initial investment less our share of BUCKLER’s startup costs, in accordance with the terms of the operating agreement of BUCKLER that our independent directors negotiated. The intended purpose of the investment in BUCKLER is to facilitate access to repurchase financing for the Company, on potentially more attractive terms (based upon the combination of rate, term, size, haircut, stability and reliability generally available in the market for comparable securities transactions) than are available through third party brokers and dealers in the repurchase financing market, or from other suitable counterparties. Our operating agreement with BUCKLER contains certain provisions to benefit and protect the Company, including (1) sharing in any (a) defined profits realized by BUCKLER from the anticipated financing spreads resulting from repurchase financing facilitated by BUCKLER, and (b) distributions from BUCKLER to its members of net cash receipts, and (2) the realization of anticipated savings from reduced clearing, brokerage, trading and administrative fees. There were no defined profits realized for the year ended December 31, 2017 . In addition, the independent directors of the Company, must approve in their sole discretion, any third-party business engaged by BUCKLER and may cause BUCKLER to wind up and dissolve and promptly return certain subordinated loans we provide to BUCKLER (as described more below) if the independent directors reasonably determine that BUCKLER’s ability to provide attractive securities transactions for the Company is materially adversely affected. BUCKLER began trading operations on October 25, 2017. The Company has entered three subordinated loan agreements with BUCKLER, totaling $105.0 million . The loans have a stated interest rate of zero , plus additional interest payable to us in an amount equal to the amount of interest earned by BUCKLER on the investment of the loan proceeds generally in government securities funds. In the first quarter of 2018, BUCKLER has paid the Company $280 of interest on these loans. The loans are repayable as follows: • $25.0 million due April 25, 2020. BUCKLER may at its option after obtaining the approval of the Financial Industry Regulatory Authority repay all or a portion of the principal amount of the loan any time after April 21, 2018. • $15.0 million due August 31, 2020. BUCKLER may at its option after obtaining the approval of the Financial Industry Regulatory Authority repay all or a portion of the principal amount of the loan any time after August 29, 2018. • $65.0 million due August 31, 2019. BUCKLER may at its option after obtaining the approval of the Financial Industry Regulatory Authority repay all or a portion of the principal amount of the loan any time after August 29, 2018. See also Note 8 , “ Repurchase Agreements ” for transactions with BUCKLER.

Acquisition of JAVELIN Mortgage

Acquisition of JAVELIN Mortgage Investment Corp.	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Acquisition of JAVELIN Mortgage Investment Corp.	Note 16 -Acquisition of JAVELIN Mortgage Investment Corp. On April 6, 2016, we completed our acquisition of all of the outstanding common stock of JAVELIN upon the merger of Acquisition with and into JAVELIN, for cash consideration of $85,200 . Subsequently, JAVELIN became a wholly-owned subsidiary of ARMOUR and continues to be managed by ACM pursuant to the pre-existing management agreement between JAVELIN and ACM. The acquisition expanded and diversified our investment portfolio. JAVELIN's complementary assets provided us with investment opportunities in Credit Risk and Non-Agency Securities MBS. We recognized JAVELIN’s assets and liabilities (including JAVELIN’s liability under JAVELIN’s management agreement with ACM) at their fair values on the date of the Merger. None of the bargain purchase price reflected in the table below was included in income for income tax purposes. The following table summarizes the consideration paid for JAVELIN and the amounts of the assets acquired and liabilities assumed recognized at the acquisition date, as well as the fair value at the acquisition date (amounts in millions): Consideration: Cash $ 85.2 Fair value of consideration transferred $ 85.2 Acquisition related costs (included in professional fees and other expenses) $ 2.5 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash $ 12.0 Cash collateral 24.6 Agency Securities 440.7 Credit Risk and Non-Agency Securities 223.2 Accrued interest receivable 1.4 Prepaid and other assets 5.4 Repurchase agreements (589.6 ) Derivatives (17.5 ) Accrued interest payable (0.9 ) Accounts payable and other accrued expenses (7.6 ) Total identifiable net assets $ 91.7 Bargain purchase price (6.5 ) Total $ 85.2 Included in accounts payable and other accrued expenses was a liability of $3,375 which was recognized as the fair value of JAVELIN’s management agreement with ACM as of April 6, 2016. This liability has been paid in full at December 31, 2017 . Total interest income of $10,784 and $13,986 and net (loss) income of $(1,683) and $15,171 are included in the consolidated statements of operations from the operations of JAVELIN for the years ended December 31, 2017 and December 31, 2016 , respectively. Total identifiable net assets of $79,475 and $105,580 are included in the consolidated balance sheets at December 31, 2017 , December 31, 2016 , respectively.

Interest Rate Risk

Interest Rate Risk	12 Months Ended
	Dec. 31, 2017
Interest Rate Risk [Abstract]
Interest Rate Risk	Note 17 -Interest Rate Risk Our primary market risk is interest rate risk. Interest rates are highly sensitive to many factors, including governmental monetary and tax policies, domestic and international economic and political considerations and other factors beyond our control. Changes in the general level of interest rates can affect net interest income, which is the difference between the interest income earned and the interest expense incurred in connection with the liabilities, by affecting the spread between the interest-earning assets and interest-bearing liabilities. Changes in the level of interest rates also can affect the value of MBS and our ability to realize gains from the sale of these assets. A decline in the value of the MBS pledged as collateral for borrowings under repurchase agreements could result in the counterparties demanding additional collateral pledges or liquidation of some of the existing collateral to reduce borrowing levels.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	Note 18 -Subsequent Events From January 2, 2018 through January 26, 2018 we sold 107 shares of our Series B Preferred Stock under the Preferred B ATM Sales Agreement for net proceeds of approximately $2,632 . On January 27, 2018, a cash dividend of $0.17 per outstanding share of Series A Preferred Stock, or $375 in the aggregate, and $0.16 per outstanding share of Series B Preferred Stock, or $1,039 in the aggregate, was paid to holders of record on January 15, 2018. We have also declared cash dividends of $0.17 and $0.16 per outstanding share of Series A Preferred Stock and Series B Preferred Stock, respectively, payable February 27, 2018 to holders of record on February 15, 2018 and payable March 27, 2018 to holders of record on March 15, 2018. On January 29, 2018, a cash dividend of $0.19 per outstanding common share, or $8,046 in the aggregate, was paid to holders of record on January 16, 2018. We have also declared a cash dividend of $0.19 per outstanding common share payable February 27, 2018 to holders of record on February 15, 2018.

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (unaudited)	Note 19 -Quarterly Financial Data (unaudited) The following tables are a comparative breakdown of our unaudited quarterly financial results for the immediately preceding eight quarters. Quarter Ended March 31, June 30, September 30, December 31, Agency Securities, net of amortization of premium and fees (2) $ 44,081 $ 44,937 $ 52,292 54,991 Credit Risk and Non-Agency Securities, including discount accretion 13,898 14,514 13,973 13,584 Interest-Only Securities 603 577 516 467 Interest expense- repurchase agreements (18,064 ) (20,516 ) (27,137 ) (28,841 ) Net Interest Income $ 40,518 $ 39,512 $ 39,644 40,201 Realized gain (loss) on sale of Agency Securities (reclassified from Other comprehensive income (loss)) (11,154 ) (460 ) 891 2,237 Other than temporary impairment of Agency Securities — (10,338 ) (72 ) (3,297 ) Gain on Credit Risk and Non-Agency Securities 24,284 30,211 (7,571 ) 18,748 Gain (Loss) on Interest-Only Securities (3,743 ) 1,286 (183 ) (326 ) Realized gain (loss) on derivatives (1) (12,249 ) 9,641 897 (20,964 ) Unrealized gain (loss) on derivatives 23,768 (30,789 ) 2,574 43,719 Expenses (2) (8,706 ) (9,364 ) (8,456 ) (9,305 ) Net Income (Loss) $ 52,718 $ 29,699 $ 27,724 71,013 Dividends declared on preferred stock (3,905 ) (3,905 ) (3,940 ) (4,130 ) Net Income (Loss) available (related) to common stockholders $ 48,813 $ 25,794 $ 23,784 $ 66,883 Net income (loss) available (related) per share to common stockholders – Basic $ 1.33 $ 0.70 $ 0.58 $ 1.60 Net income (loss) available (related) per share to common stockholders – Diluted $ 1.33 $ 0.70 $ 0.58 $ 1.58 Dividends declared per common share $ 0.57 $ 0.57 $ 0.57 $ 0.57 Weighted average common shares outstanding – Basic 36,724 36,782 41,288 41,857 Weighted average common shares outstanding – Diluted 36,748 36,798 41,296 42,329 (1) Interest expense related to our interest rate swap contracts is recorded in realized loss on derivatives on the consolidated statements of operations. Quarter Ended March 31, June 30, September 30, December 31, Agency Securities, net of amortization of premium and fees (2) $ 78,650 $ 55,539 $ 44,544 $ 47,063 Credit Risk and Non-Agency Securities, including discount accretion 327 9,853 12,969 13,424 Interest-Only Securities — 3 852 771 Interest expense- repurchase agreements (19,148 ) (18,276 ) (17,040 ) (18,643 ) Net Interest Income $ 59,829 $ 47,119 $ 41,325 $ 42,615 Realized gain (loss) on sale of Agency Securities (reclassified from Other comprehensive income (loss)) 1,891 14,625 2,421 (37,147 ) Other than temporary impairment of Agency Securities — — — (6,540 ) Gain on Credit Risk and Non-Agency Securities 4,122 10,151 39,522 5,325 Gain (Loss) on Interest-Only Securities — (1,243 ) (1,105 ) 8,778 Bargain purchase price on acquisition of JAVELIN — 6,484 — — Realized gain (loss) on derivatives (1) (246,105 ) (112,515 ) 19,816 (113,594 ) Unrealized gain (loss) on derivatives (89,058 ) 66,141 25,824 203,305 Expenses (2) (10,154 ) (9,587 ) (9,115 ) (8,647 ) Net Income (Loss) $ (279,475 ) $ 21,175 $ 118,688 $ 94,095 Dividends declared on preferred stock (3,905 ) (3,905 ) (3,905 ) (3,906 ) Net Income (Loss) available (related) to common stockholders $ (283,380 ) $ 17,270 $ 114,783 $ 90,189 Net income (loss) available (related) per share to common stockholders – Basic $ (7.73 ) $ 0.47 $ 3.13 $ 2.46 Net income (loss) available (related) per share to common stockholders – Diluted $ (7.73 ) $ 0.47 $ 3.12 $ 2.45 Dividends declared per common share $ 0.99 $ 0.71 $ 0.66 $ 0.66 Weighted average common shares outstanding – Basic 36,683 36,693 36,703 36,713 Weighted average common shares outstanding – Diluted 36,683 36,748 36,746 36,745 (1) Interest expense related to our interest rate swap contracts is recorded in realized loss on derivatives on the consolidated statements of operations. (2) Certain amounts included in other expenses in the first and second quarters of 2016 have been reclassified to Interest Income Agency Securities.

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2017
Accounting Policies [Abstract]
Basis of Presentation	The accompanying consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the U.S. (“GAAP”). The consolidated financial statements include the accounts of ARMOUR Residential REIT, Inc. and its subsidiaries including the results of JAVELIN Mortgage Investment Corp. since its acquisition on April 6, 2016 (see also Note 16 “ Acquisition of JAVELIN Mortgage Investment Corp. ”). All intercompany accounts and transactions have been eliminated. 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 disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates affecting the accompanying consolidated financial statements include the valuation of MBS (as defined below), including an assessment of whether other-than-temporary impairment (“OTTI”) exists, and derivative instruments.
Cash	Cash Cash includes cash on deposit with financial institutions. We may maintain deposits in federally insured financial institutions in excess of federally insured limits. However, management believes we are not exposed to significant credit risk 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 Cash collateral posted to/by counterparties represents cash posted by us to counterparties or posted by counterparties to us as collateral. Cash collateral posted to/by counterparties may include collateral for interest rate swap contracts (including swaptions and basis swap contracts), Eurodollar Futures Contracts (“Futures Contracts”) and repurchase agreements on our MBS and our Agency Securities purchased or sold on a to-be-announced basis (“TBA Agency Securities”).
Fair Value of MBS and Agency Securities	MBS, at Fair Value We generally intend to hold most of our MBS for extended periods of time. We may, from time to time, sell any of our MBS as part of the overall management of our MBS portfolio. Management determines the appropriate classifications of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. Purchases and sales of our MBS are recorded on the trade date. Fair Value of Agency Securities: We invest in Agency Securities representing interests in or obligations backed by pools of fixed rate, hybrid adjustable rate and adjustable rate mortgage loans. GAAP requires us to classify our investments as either trading, available for sale or held to maturity securities. Management determines the appropriate classifications of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. We currently classify all of our Agency Securities as available for sale. Agency Securities classified as available for sale are reported at their estimated fair values with unrealized gains and losses excluded from earnings and reported as part of the statements of comprehensive income (loss). Security purchase and sale transactions, including purchase of TBA Agency Securities, are recorded on the trade date to the extent it is probable that we will take or make timely physical delivery of the related securities. Gains or losses realized from the sale of securities are included in income and are determined using the specific identification method.
Agency Securities, Available for Sale	Agency Securities, Available For Sale - At December 31, 2017 and December 31, 2016 , all of our Agency Securities were classified as available for sale securities. Agency Securities classified as available for sale are reported at their estimated fair values with unrealized gains and losses excluded from earnings and reported as part of the consolidated statements of comprehensive income (loss).
Credit Risk, Non-Agency, and Interest-only Securities, Trading	Credit Risk and Non-Agency Securities, Trading - At December 31, 2017 and December 31, 2016 , all of our Credit Risk and Non-Agency Securities were classified as trading securities. Credit Risk and Non-Agency Securities classified as trading are reported at their estimated fair values with unrealized gains and losses included in Other Income (Loss) as a component of the consolidated statements of operations. Interest-only Securities, Trading - At December 31, 2017 and December 31, 2016 , all of our Interest-only Securities were classified as trading securities. Interest-only Securities represent the right to receive a specified proportion of the contractual interest flows of specific Agency MBS. Interest-only Securities classified as trading are reported at their estimated fair values with unrealized gains and losses included in Other Income (Loss) as a component of the consolidated statements of operations.
Receivables and Payables for Unsettled Sales and Purchases	Receivables and Payables for Unsettled Sales and Purchases We account for purchases and sales of securities on the trade date, including purchases and sales for forward settlement. Receivables and payables for unsettled trades represent the agreed trade price multiplied by the outstanding balance of the securities at the balance sheet date.
Accrued Interest Receivable and Payable	Accrued Interest Receivable and Payable Accrued interest receivable includes interest accrued between payment dates on MBS. Accrued interest payable includes interest payable on our repurchase agreements and may, at certain times, contain interest payable on U.S. Treasury Securities sold short.
Repurchase Agreements	Repurchase Agreements We finance the acquisition of our MBS through the use of repurchase agreements. Our repurchase agreements are secured by our MBS and bear interest rates that have historically moved in close relationship to the Federal Funds Rate and the London Interbank Offered Rate (“LIBOR”). Under these repurchase agreements, we sell MBS to a lender and agree to repurchase the same MBS in the future for a price that is higher than the original sales price. The difference between the sales price that we receive and the repurchase price that we pay represents interest paid to the lender. A repurchase agreement operates as a financing arrangement under which we pledge our MBS as collateral to secure a loan which is equal in value to a specified percentage of the estimated fair value of the pledged collateral. We retain beneficial ownership of the pledged collateral. At the maturity of a repurchase agreement, we are required to repay the loan and concurrently receive back our pledged collateral from the lender or, with the consent of the lender, we may renew such agreement at the then prevailing interest rate. The repurchase agreements may require us to pledge additional assets to the lender in the event the estimated fair value of the existing pledged collateral declines. In addition to the repurchase agreement financing discussed above, at certain times we have entered into reverse repurchase agreements with certain of our repurchase agreement counterparties. Under a typical reverse repurchase agreement, we purchase U.S. Treasury Securities from a borrower in exchange for cash and agree to sell the same securities in the future in exchange for a price that is higher than the original purchase price. The difference between the purchase price originally paid and the sale price represents interest received from the borrower. Reverse repurchase agreement receivables and repurchase agreement liabilities are presented net when they meet certain criteria, including being with the same counterparty, being governed by the same master repurchase agreement (“MRA”), settlement through the same brokerage or clearing account and maturing on the same day.
Obligations to Return Securities Received as Collateral, at Fair Value	Obligations to Return Securities Received as Collateral, at Fair Value At certain times, we also sell to third parties the U.S. Treasury Securities received as collateral for reverse repurchase agreements and recognize the resulting obligation to return said U.S. Treasury Securities as a liability on our consolidated balance sheets. Interest is recorded on the repurchase agreements, reverse repurchase agreements and U.S. Treasury Securities sold short on an accrual basis and presented as interest expense. Both parties to the transaction have the right to make daily margin calls based on changes in the fair value of the collateral received and/or pledged.
Derivatives, at Fair Value	Derivatives, at Fair Value We recognize all derivatives as either assets or liabilities at fair value on our consolidated balance sheets. All changes in the fair values of our derivatives are reflected in our consolidated statements of operations. We designate derivatives as hedges for tax purposes and any unrealized derivative gains or losses would not affect our distributable net taxable income. These transactions include interest rate swap contracts, interest rate swaptions and basis swap contracts. We also may utilize forward contracts for the purchase or sale of TBA Agency Securities. We account for TBA Agency Securities as derivative instruments if it is reasonably possible that we will not take or make physical delivery of the Agency Security upon settlement of the contract. We account for TBA dollar roll transactions as a series of derivative transactions. We may also purchase and sell TBA Agency Securities as a means of investing in and financing Agency Securities (thereby increasing our “at risk” leverage) or as a means of disposing of or reducing our exposure to Agency Securities (thereby reducing our “at risk” leverage). Pursuant to TBA Agency Securities, we agree to purchase or sell, for future delivery, Agency Securities 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 TBA settlement date. We may also choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting short or long position (referred to as a “pair off”), net settling the paired off positions for cash, and simultaneously purchasing or selling a similar TBA Agency Security for a later settlement date. This transaction is commonly referred to as a “dollar roll.” When it is reasonably possible that we will pair off a TBA Agency Security, we account for that contract as a derivative.
Revenue Recognition	Revenue Recognition Agency Securities, Available For Sale - Interest income is earned and recognized on Agency Securities based on their unpaid principal amounts and their contractual terms. Recognition of interest income commences on the settlement date of the purchase transaction and continues through the settlement date of the sale transaction. Premiums and discounts associated with the purchase of Multi-Family MBS, which are generally not subject to prepayment, are amortized or accreted into interest income over the contractual lives of the securities using a level yield method. Premiums and discounts associated with the purchase of other Agency Securities are amortized or accreted into interest income over the actual lives of the securities, reflecting actual prepayments as they occur. Credit Risk and Non-Agency Securities and Interest-Only Securities, Trading - Interest income on Credit Risk and Non-Agency Securities and Interest-only Securities is recognized using the effective yield method over the life of the securities based on the future cash flows expected to be received. Future cash flow projections and related effective yields are determined for each security and updated quarterly. Other than temporary impairments, which establish a new cost basis in the security for purposes of calculating effective yields, are recognized when the fair value of a security is less than its cost basis and there has been an adverse change in the future cash flows expected to be received. Other changes in future cash flows expected to be received are recognized prospectively over the remaining life of the security.
Impairment of Assets	Impairment of Assets: We evaluate Agency Securities for other than temporary impairment at least on a quarterly basis and more frequently when economic or market concerns warrant such evaluation. We consider an impairment to be other than temporary if we (1) have the intent to sell the Agency Securities, (2) believe it is more likely than not that we will be required to sell the securities before recovery (for example, because of liquidity requirements or contractual obligations) or (3) a credit loss exists. Impairment losses recognized establish a new cost basis for the related Agency Securities.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) refers to changes in equity during a period from transactions and other events and circumstances from non-owner sources. It includes all changes in equity during a period, except those resulting from investments by owners and distributions to owners.
Recent Accounting Pronouncements	In August 2017, the Financial Accounting Standards Board issued ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities . The standard amends the hedge accounting recognition and presentation requirements in ASC 815. The standard is effective for fiscal years beginning after December 15, 2018 and interim periods therein, however, early adoption is permitted upon its issuance. The Company is currently assessing the impact of the standard and whether it may apply hedge accounting in the future. In February 2016, the Financial Accounting Standards Board issued ASU 2016-02, Leases (Topic 842). The standard introduces a new lessee model that will require most leases to be recorded on the balance sheet recognizing a right-of-use lease asset and a liability to make lease payments. The standard will be effective for annual periods beginning after December 15, 2018. As the Company has no leases this standard will have no impact on the consolidated financial statements in future periods. In July 2016, the Financial Accounting Standards Board issued ASU 2016-13, Financial Instruments–Credit Losses (Topic 326) . The standard introduces a new model for recognizing credit losses on financial instruments based on an estimate of current expected credit losses. The standard will apply to (1) loans, accounts receivable, trade receivables, and other financial assets measured at amortized cost, (2) loan commitments and certain other off–balance sheet credit exposures, (3) debt securities and other financial assets measured at fair value through other comprehensive income, and (4) beneficial interests in securitized financial assets. The standard is effective for fiscal years beginning after December 15, 2019. The Company is assessing the impact of this standard but does not expect it to have significant impact on the consolidated financial statements. However, the impact on the consolidated financial statements will depend on the debt securities held by the Company on the date of the adoption.

Fair Value of Financial Instr28

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance at December 31, 2016 Assets at Fair Value: Agency Securities, available for sale $ — $ 6,511,164 $ — $ 6,511,164 Credit Risk and Non-Agency Securities, trading $ — $ — $ 1,052,170 $ 1,052,170 Interest-Only Securities, trading $ — $ 33,627 $ — $ 33,627 Derivatives $ — $ 9,837 $ — $ 9,837 Liabilities at Fair Value: Derivatives $ — $ 49,655 $ — $ 49,655 The following tables provide a summary of our assets and liabilities that are measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016 . Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Balance at December 31, 2017 Assets at Fair Value: Agency Securities, available for sale $ — $ 7,478,966 $ — $ 7,478,966 Credit Risk and Non-Agency Securities, trading $ — $ 975,829 $ — $ 975,829 Interest-Only Securities, trading $ — $ 25,752 $ — $ 25,752 Derivatives $ — $ 37,211 $ — $ 37,211 Liabilities at Fair Value: Derivatives $ — $ 7,948 $ — $ 7,948
Carrying Values and Fair Values of Financial Assets and Liabilities	The following tables provide a summary of the carrying values and fair values of our financial assets and liabilities not carried at fair value but for which fair value is required to be disclosed at December 31, 2017 and December 31, 2016 . December 31, 2017 Fair Value Measurements using: Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash $ 265,232 $ 265,232 $ 265,232 $ — $ — Cash collateral posted to counterparties $ 17,162 $ 17,162 $ — $ 17,162 $ — Accrued interest receivable $ 22,165 $ 22,165 $ — $ 22,165 $ — Subordinated loans due from BUCKLER Securities LLC $ 105,000 $ 105,000 $ — $ 105,000 — Financial Liabilities: Repurchase agreements $ 7,555,917 $ 7,555,917 $ — $ 7,555,917 $ — Cash collateral posted by counterparties $ 29,593 $ 29,593 $ — $ 29,593 $ — Accrued interest payable- repurchase agreements $ 6,452 $ 6,452 $ — $ 6,452 $ — December 31, 2016 Fair Value Measurements using: Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Financial Assets: Cash $ 271,773 $ 271,773 $ 271,773 $ — $ — Cash collateral posted to counterparties $ 79,471 $ 79,471 $ — $ 79,471 $ — Accrued interest receivable $ 18,452 $ 18,452 $ — $ 18,452 $ — Financial Liabilities: Repurchase agreements $ 6,818,453 $ 6,818,453 $ — $ 6,818,453 $ — Cash collateral posted by counterparties $ 3,774 $ 3,774 $ — $ 3,774 $ — Accrued interest payable- repurchase agreements $ 6,934 $ 6,934 $ — $ 6,934 $ —
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table provides a summary of the changes in Level 3 assets measured at fair value on a recurring basis at December 31, 2017 and December 31, 2016 . For the Years Ended Credit Risk and Non-Agency Securities December 31, 2017 December 31, 2016 Balance, beginning of year (1) $ 1,052,170 $ — Credit Risk and Non-Agency Securities acquired in the acquisition of JAVELIN, at fair value — 223,220 Purchases of Credit Risk and Non-Agency Securities, at cost 8,224 882,588 Principal repayments of Credit Risk and Non-Agency Securities (135,617 ) (53,033 ) Proceeds from the sale of Credit Risk and Non-Agency Securities (8,372 ) (61,843 ) Gain on Credit Risk and Non-Agency Securities 46,924 59,120 Accretion of net discount on Credit Risk and Non-Agency Securities 3,187 2,118 Level 3 transferred to Level 2 (966,516 ) — Balance, end of year $ — $ 1,052,170 Gain on Credit Risk and Non-Agency Securities $ 54,495 $ 59,120 (1) We did not have any Level 3 assets at December 31, 2015 .
Fair Value Inputs, Instruments Classified in Shareholders' Equity, Quantitative Information	The following table presents the range of our estimates of cumulative default and loss severities, together with the discount rates implicit in our Level 3 Credit Risk and Non-Agency Securities Security fair values at December 31, 2016 . Unobservable Level 3 Input Minimum Weighted Average Maximum Cumulative default 0.00 % 2.15 % 55.49 % Loss severity (life) 0.00 % 29.01 % 68.40 % Discount rate 3.62 % 4.47 % 5.50 % Delinquency (life) 0.00 % 4.84 % 50.10 % Voluntary prepayments (life) 1.50 % 8.72 % 14.60 %

Agency Securities, Available 29

Agency Securities, Available for Sale (Tables)	12 Months Ended
	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities	At December 31, 2017 , we had the following Agency Securities in an unrealized gain or loss position as presented below. The components of the carrying value of our Agency Securities at December 31, 2017 are also presented below. Our Agency Securities had a weighted average coupon of 3.68% at December 31, 2017 . December 31, 2017 Amortized Cost Gross Unrealized Loss Gross Unrealized Gain Fair Value Percent of Total Fannie Mae ARMs & Hybrids $ 28,199 $ (229 ) $ 112 $ 28,082 0.38 % Multi-Family MBS 1,799,737 (5,132 ) 16,950 1,811,555 24.22 10 Year Fixed 60,634 (347 ) 137 60,424 0.81 15 Year Fixed 1,028,797 (4,955 ) 625 1,024,467 13.70 20 Year Fixed 29,832 (621 ) — 29,211 0.39 25 Year Fixed 9,367 (140 ) — 9,227 0.12 30 Year Fixed 2,938,655 (18,910 ) 431 2,920,176 39.05 Total Fannie Mae $ 5,895,221 $ (30,334 ) $ 18,255 $ 5,883,142 78.67 % Freddie Mac 10 Year Fixed 37,254 (158 ) 228 37,324 0.50 15 Year Fixed 354,878 (211 ) 787 355,454 4.75 25 Year Fixed 41,383 (857 ) — 40,526 0.54 30 Year Fixed 1,131,584 (7,300 ) — 1,124,284 15.03 Total Freddie Mac $ 1,565,099 $ (8,526 ) $ 1,015 $ 1,557,588 20.82 % Ginnie Mae ARMs & Hybrids 38,494 (532 ) 4 37,966 0.51 10 Year Fixed 263 — 7 270 0.00 Total Ginnie Mae $ 38,757 $ (532 ) $ 11 $ 38,236 0.51 % Total Agency Securities $ 7,499,077 $ (39,392 ) $ 19,281 $ 7,478,966 100.00 % At December 31, 2016 , we had the following securities in an unrealized gain or loss position as presented below. The components of the carrying value of our Agency Securities at December 31, 2016 are also presented below. Our Agency Securities had a weighted average coupon of 3.52% at December 31, 2016 . December 31, 2016 Amortized Cost Gross Unrealized Loss Gross Unrealized Gain Fair Value Percent of Total Fannie Mae ARMs & Hybrids $ 38,140 $ (174 ) $ 303 $ 38,269 0.60 % Multi-Family MBS 1,439,126 (5,677 ) 8,324 1,441,773 22.14 10 Year Fixed 93,440 (755 ) 335 93,020 1.43 15 Year Fixed 2,796,785 (10,424 ) 2,011 2,788,372 42.82 20 Year Fixed 338,017 (4,629 ) — 333,388 5.12 25 Year Fixed 12,126 (105 ) — 12,021 0.18 30 Year Fixed 1,062,718 (10,902 ) — 1,051,816 16.15 Total Fannie Mae $ 5,780,352 $ (32,666 ) $ 10,973 $ 5,758,659 88.44 % Freddie Mac 10 Year Fixed 48,030 (149 ) 501 48,382 0.75 15 Year Fixed 530,590 (5,876 ) 1,633 526,347 8.08 20 Year Fixed 19,503 (410 ) — 19,093 0.29 25 Year Fixed 115,442 (2,370 ) — 113,072 1.74 Total Freddie Mac $ 713,565 $ (8,805 ) $ 2,134 $ 706,894 10.86 % Ginnie Mae ARMs & Hybrids 46,092 (786 ) 3 45,309 0.70 10 Year Fixed 289 — 13 302 0.00 Total Ginnie Mae $ 46,381 $ (786 ) $ 16 $ 45,611 0.70 % Total Agency Securities $ 6,540,298 $ (42,257 ) $ 13,123 $ 6,511,164 100.00 %
Investments Classified by Contractual Maturity Date	The following table summarizes the weighted average lives of our Agency Securities at December 31, 2017 and December 31, 2016 . December 31, 2017 December 31, 2016 Weighted Average Life of all Agency Securities Fair Value Amortized Cost Fair Value Amortized Cost Less than one year $ — $ — $ 4 $ 5 Greater than or equal to one year and less than three years 29,126 29,269 17,773 17,998 Greater than or equal to three years and less than five years 1,353,036 1,353,998 3,237,524 3,248,401 Greater than or equal to five years 6,096,804 6,115,810 3,255,863 3,273,894 Total Agency Securities $ 7,478,966 $ 7,499,077 $ 6,511,164 $ 6,540,298
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	The following table presents the unrealized losses and estimated fair value of our Agency Securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2017 and December 31, 2016 . Unrealized Loss Position For: Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 $ 4,355,924 $ (28,906 ) $ 733,637 $ (10,486 ) $ 5,089,561 $ (39,392 ) December 31, 2016 $ 4,069,170 $ (41,045 ) $ 61,133 $ (1,212 ) $ 4,130,303 $ (42,257 )

Credit Risk and Non-Agency Se30

Credit Risk and Non-Agency Securities, Trading (Tables)	12 Months Ended
	Dec. 31, 2017
Schedule of Trading Securities and Other Trading Assets [Line Items]
Investments Classified by Contractual Maturity Date	The following table summarizes the weighted average lives of our Agency Securities at December 31, 2017 and December 31, 2016 . December 31, 2017 December 31, 2016 Weighted Average Life of all Agency Securities Fair Value Amortized Cost Fair Value Amortized Cost Less than one year $ — $ — $ 4 $ 5 Greater than or equal to one year and less than three years 29,126 29,269 17,773 17,998 Greater than or equal to three years and less than five years 1,353,036 1,353,998 3,237,524 3,248,401 Greater than or equal to five years 6,096,804 6,115,810 3,255,863 3,273,894 Total Agency Securities $ 7,478,966 $ 7,499,077 $ 6,511,164 $ 6,540,298
Credit Risk and Non-Agency Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Carrying Value of Non-Agency Securities	The components of the carrying value of our Credit Risk and Non-Agency Securities at December 31, 2017 are presented in the table below. Credit Risk and Non-Agency Securities December 31, 2017 Fair Value Amortized Cost Principal Amount Weighted Average Coupon Credit Risk Transfer $ 870,494 $ 753,422 $ 764,172 6.05 % Legacy Prime Fixed 16,778 15,287 19,237 6.03 % Legacy ALT-A Fixed 54,727 48,516 65,920 5.85 % Legacy Prime Hybrid 10,469 9,517 11,452 3.17 % Legacy ALT-A Hybrid 4,660 3,895 4,901 3.47 % New Issue Prime Fixed 18,701 17,957 — 19,025 3.69 % Total Credit Risk and Non-Agency Securities $ 975,829 $ 848,594 $ 884,707 5.95 % The components of the carrying value of our Credit Risk and Non-Agency Securities at December 31, 2016 are presented in the table below. Credit Risk and Non-Agency Securities December 31, 2016 Fair Value Amortized Cost Principal Amount Weighted Average Coupon Credit Risk Transfer $ 821,343 $ 764,982 $ 778,216 5.26% NPL/RPL 122,802 121,869 122,561 3.80% Legacy Prime Fixed 19,954 19,406 24,409 6.03% Legacy ALT-A Fixed 59,253 56,776 76,151 5.85% Legacy Prime Hybrid 11,914 11,163 13,641 2.72% Legacy ALT-A Hybrid 6,039 5,669 6,956 3.01% New Issue Prime Fixed 10,865 10,708 11,324 3.66% Total Credit Risk and Non-Agency Securities $ 1,052,170 $ 990,573 $ 1,033,258 5.08%
Investments Classified by Contractual Maturity Date	The following table summarizes the weighted average lives of our Credit Risk and Non-Agency Securities at December 31, 2017 and December 31, 2016 . December 31, 2017 December 31, 2016 Weighted Average Life of all Credit Risk and Non-Agency Securities Fair Value Amortized Cost Fair Value Amortized Cost Less than one year $ — $ — $ — $ — Greater than or equal to one year and less than three years — — 122,802 121,869 Greater than or equal to three years and less than five years 169,189 149,436 94,839 88,750 Greater than or equal to five years 806,640 699,158 834,529 779,954 Total Credit Risk and Non-Agency Securities $ 975,829 $ 848,594 $ 1,052,170 $ 990,573
Continuous Unrealized Loss Position, Non-Agency Securities	The following table presents the unrealized losses and estimated fair value of our Credit Risk and Non-Agency Securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2017 and December 31, 2016 . Unrealized Loss Position For: Less than 12 Months 12 Months or More Total As of Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses December 31, 2017 $ — $ — $ — $ — $ — $ — December 31, 2016 $ 2,022 $ (14 ) $ — $ — $ 2,022 $ (14 )

Repurchase Agreements (Tables)

Repurchase Agreements (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Repurchase Agreements [Abstract]
Schedule of Repurchase Agreements	The following table represents the contractual repricing regarding our repurchase agreements to finance MBS purchases at December 31, 2017 and December 31, 2016 . No amounts below are subject to offsetting. December 31, 2017 Repurchase Agreements Weighted Average Contractual Rate Weighted Average Maturity in days Haircut for Repurchase Agreements (1) Agency Securities $ 6,793,481 1.60 % 55 4.29 % Credit Risk and Non-Agency Securities 762,436 2.67 % 15 21.68 % Total or Weighted Average $ 7,555,917 1.71 % 51 6.39 % (1) The Haircut represents the weighted average margin requirement, or the percentage amount by which the collateral value must exceed the loan amount. December 31, 2016 Repurchase Agreements Weighted Average Contractual Rate Weighted Average Maturity in days Haircut for Repurchase Agreements (1) Agency Securities $ 6,017,843 0.92 % 22 4.70 % Credit Risk and Non-Agency Securities 778,015 2.26 % 23 23.82 % U.S. Treasury Securities 22,595 0.46 % 3 1.11 % Total or Weighted Average $ 6,818,453 1.07 % 22 7.45 % (1) The Haircut represents the weighted average margin requirement, or the percentage amount by which the collateral value must exceed the loan amount. December 31, 2017 December 31, 2016 Maturing or Repricing Repurchase Agreements Weighted Average Contractual Rate Repurchase Agreements Weighted Average Contractual Rate Within 30 days $ 1,738,768 2.08 % $ 5,082,076 1.11 % 31 days to 60 days 2,394,450 1.59 % 1,699,197 0.94 % 61 days to 90 days 3,422,699 1.61 % 37,180 2.38 % Greater than 90 days — 0.00 % — — % Total or Weighted Average $ 7,555,917 1.71 % $ 6,818,453 1.07 % During the years ended December 31, 2017 and December 31, 2016 , we did not repurchase any shares of our common stock. December 31, 2015 Transaction Type Completion Date Number of Per Share price (1) Net Cost Repurchased common shares March 5, 2015-December 31, 2015 7,510 $ 21.25 $ 159,600 (1) Weighted average price

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2017
Derivative [Line Items]
Schedule of Derivative Instruments	The following tables present information about our derivatives at December 31, 2017 and December 31, 2016 . December 31, 2017 Derivative Type Remaining / Underlying Term Weighted Average Remaining Swap / Option Term (Months) Weighted Average Rate Notional Amount Asset Fair Value (1) Liability Fair Value (1) Interest rate swap contracts 0-12 Months 5 0.92 % $ 50,000 $ 191 $ — Interest rate swap contracts 13-24 Months 23 1.21 % 550,000 6,398 — Interest rate swap contracts 25-36 Months 30 1.48 % 675,000 5,495 — Interest rate swap contracts 61-72 Months 65 1.97 % 1,975,000 11,624 (250 ) Interest rate swap contracts 73-84 Months 79 1.89 % 575,000 3,306 (1,885 ) Interest rate swap contracts 97-108 Months 107 1.93 % 1,050,000 9,263 (10 ) Interest rate swap contracts 109-120 Months 114 2.10 % 375,000 — (3,545 ) TBA Agency Securities (2) 0-60 Months n/a n/a 1,600,000 934 (2,258 ) Total or Weighted Average $ 6,850,000 $ 37,211 $ (7,948 ) (1) See Note 5 , “ Fair Value of Financial Instruments ” for additional discussion. (2) Implied cost basis of $1,674,438 and implied market value of $1,673,113 . December 31, 2016 Derivative Type Remaining / Underlying Term Weighted Average Remaining Swap / Option Term (Months) Weighted Average Rate Notional Amount (3) Asset Fair Value (1) Liability Fair Value (1) Interest rate swap contracts 0-12 Months 7 0.54 % $ 200,000 $ 158 $ — Interest rate swap contracts 13-24 Months 17 0.92 % 50,000 — (117 ) Interest rate swap contracts 25-36 Months 35 1.21 % 550,000 1,547 — Interest rate swap contracts 73-84 Months 77 1.97 % 2,075,000 3,690 (10,767 ) Interest rate swap contracts 85-96 Months 84 1.97 % 100,000 — (1,242 ) Interest rate swap contracts 109-120 Months 119 1.95 % 1,250,000 2,378 (2,278 ) TBA Agency Securities (2) 0-60 Months n/a n/a 2,850,000 2,064 (35,251 ) Total or Weighted Average $ 7,075,000 $ 9,837 $ (49,655 ) (1) See Note 5, “Fair Value of Financial Instruments” for additional discussion. (2) Implied cost basis of $2,922,582 and implied market value of $2,889,395 . (3) Notional amount includes $300,000 of forward starting interest rate swap contracts which became effective on January 3, 2017.
Derivative Instruments, Gain (Loss)	The following table represents the location and information regarding our derivatives which are included in Other Income (Loss) in the accompanying consolidated statements of operations for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . Income (Loss) Recognized For the Year Ended Derivatives Location on consolidated statements of operations December 31, 2017 December 31, 2016 December 31, 2015 Interest rate swap contracts: Realized gain (loss) Realized loss on derivatives $ 990 $ (370,192 ) $ (2,274 ) Interest income Realized loss on derivatives 50,464 25,270 13,066 Interest expense Realized loss on derivatives (83,797 ) (90,978 ) (123,929 ) Changes in fair value Unrealized gain (loss) on derivatives 39,388 208,082 (182,503 ) $ 7,045 $ (227,818 ) $ (295,640 ) Futures Contracts: Realized loss Realized loss on derivatives — — (184 ) Changes in fair value Unrealized gain (loss) on derivatives — — 180 $ — $ — $ (4 ) Basis swap contracts: Realized gain Realized loss on derivatives — 1,468 — Interest income Realized loss on derivatives — 2,617 803 Interest expense Realized loss on derivatives — (3,116 ) (922 ) Changes in fair value Unrealized gain (loss) on derivatives — (661 ) 661 $ — $ 308 $ 542 TBA Agency Securities: Realized gain (loss) Realized loss on derivatives 9,668 (17,467 ) 6,370 Changes in fair value Unrealized gain (loss) on derivatives (116 ) (1,209 ) — $ 9,552 $ (18,676 ) $ 6,370 Totals $ 16,597 $ (246,186 ) $ (288,732 )
Derivative
Derivative [Line Items]
Offsetting Assets	The following tables present information about interest rate swap contracts and Agency Securities TBA and the potential effects of netting if we were to offset the assets and liabilities of these financial instruments on the accompanying consolidated balance sheets. Currently, we present these financial instruments at their gross amounts and they are included in derivatives, at fair value on the accompanying consolidated balance sheet at December 31, 2017 . December 31, 2017 Gross Amounts Not Offset in the Consolidated Balance Sheet Assets Gross and Net Amounts of Assets Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ 36,277 $ (5,690 ) $ (22,689 ) $ 7,898 Agency Securities TBA 934 (2,258 ) 8,068 6,744 Totals $ 37,211 $ (7,948 ) $ (14,621 ) $ 14,642 The following tables present information about interest rate swap contracts and Agency Securities TBA and the potential effects of netting if we were to offset the assets and liabilities of these financial instruments on the accompanying consolidated balance sheets. Currently, we present these financial instruments at their gross amounts and they are included in derivatives, at fair value on the accompanying consolidated balance sheet at December 31, 2016 . December 31, 2016 Gross Amounts Not Offset in the Consolidated Balance Sheet Assets Gross and Net Amounts of Assets Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ 7,773 $ (14,404 ) $ 19,395 $ 12,764 Agency Securities TBA 2,064 (35,251 ) 37,839 4,652 Totals $ 9,837 $ (49,655 ) $ 57,234 $ 17,416
Offsetting Liabilities	December 31, 2016 Gross Amounts Not Offset in the Consolidated Balance Sheet Liabilities Gross and Net Amounts of Liabilities Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ (14,404 ) $ 14,404 $ — $ — Agency Securities TBA (35,251 ) 35,251 — — Totals $ (49,655 ) $ 49,655 $ — $ — December 31, 2017 Gross Amounts Not Offset in the Consolidated Balance Sheet Liabilities Gross and Net Amounts of Liabilities Presented in the Consolidated Balance Sheet Financial Instruments Cash Collateral Net Amount Interest rate swap contracts $ (5,690 ) $ 5,690 $ — $ — Agency Securities TBA (2,258 ) 2,258 — — Totals $ (7,948 ) $ 7,948 $ — $ —

Stock Based Compensation (Table

Stock Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Nonvested Restricted Stock Units Activity	Transactions related to awards for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 are summarized below: December 31, 2017 December 31, 2016 December 31, 2015 Number of Awards Weighted Average Grant Date Fair Value per Award Number of Awards Weighted Average Grant Date Fair Value per Award Number of Awards Weighted Average Grant Date Fair Value per Award Unvested RSU Awards Outstanding beginning of period 32 $ 39.80 78 $ 48.85 132 $ 51.76 Granted 472 $ 24.82 — $ — — $ — Vested (32 ) $ 39.80 (46 ) $ 56.14 (53 ) $ 56.40 Forfeited — $ — — $ — (1 ) $ 58.90 Unvested RSU Awards Outstanding end of period 472 $ 24.82 32 $ 39.80 78 $ 48.85

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2017
Equity [Abstract]
Schedule of Repurchase Agreements	The following table represents the contractual repricing regarding our repurchase agreements to finance MBS purchases at December 31, 2017 and December 31, 2016 . No amounts below are subject to offsetting. December 31, 2017 Repurchase Agreements Weighted Average Contractual Rate Weighted Average Maturity in days Haircut for Repurchase Agreements (1) Agency Securities $ 6,793,481 1.60 % 55 4.29 % Credit Risk and Non-Agency Securities 762,436 2.67 % 15 21.68 % Total or Weighted Average $ 7,555,917 1.71 % 51 6.39 % (1) The Haircut represents the weighted average margin requirement, or the percentage amount by which the collateral value must exceed the loan amount. December 31, 2016 Repurchase Agreements Weighted Average Contractual Rate Weighted Average Maturity in days Haircut for Repurchase Agreements (1) Agency Securities $ 6,017,843 0.92 % 22 4.70 % Credit Risk and Non-Agency Securities 778,015 2.26 % 23 23.82 % U.S. Treasury Securities 22,595 0.46 % 3 1.11 % Total or Weighted Average $ 6,818,453 1.07 % 22 7.45 % (1) The Haircut represents the weighted average margin requirement, or the percentage amount by which the collateral value must exceed the loan amount. December 31, 2017 December 31, 2016 Maturing or Repricing Repurchase Agreements Weighted Average Contractual Rate Repurchase Agreements Weighted Average Contractual Rate Within 30 days $ 1,738,768 2.08 % $ 5,082,076 1.11 % 31 days to 60 days 2,394,450 1.59 % 1,699,197 0.94 % 61 days to 90 days 3,422,699 1.61 % 37,180 2.38 % Greater than 90 days — 0.00 % — — % Total or Weighted Average $ 7,555,917 1.71 % $ 6,818,453 1.07 % During the years ended December 31, 2017 and December 31, 2016 , we did not repurchase any shares of our common stock. December 31, 2015 Transaction Type Completion Date Number of Per Share price (1) Net Cost Repurchased common shares March 5, 2015-December 31, 2015 7,510 $ 21.25 $ 159,600 (1) Weighted average price
Schedule of Stockholders Equity	The following tables present our equity transactions for the years ended December 31, 2017 and December 31, 2015 . We did not have equity raising transactions for the year ended December 31, 2016 . December 31, 2017 Transaction Type Completion Date Number of Shares Per Share price (1) Net Proceeds Series B Preferred ATM Sales Agreement August 31, 2017-December 30, 2017 612 $ 24.44 $ 14,968 Common stock follow-on public offering June 30, 2017 4,500 $ 25.96 $ 116,693 Common stock dividend reinvestment program September 12, 2017-October 6, 2017 619 $ 26.44 $ 16,500 (1) Weighted average price December 31, 2015 Transaction Type Completion Date Number of Shares Per Share price (1) Net Proceeds Common stock dividend reinvestment program January 26, 2015-November 27, 2015 6 $ 23.21 $ 147 (1) Weighted average price
Dividends Transactions	The following tables present our common stock dividend transactions for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . December 31, 2017 Record Date Payment Date Rate per common share Aggregate amount paid to holders of record January 17, 2017 January 30, 2017 $ 0.19 $ 6,984 February 15, 2017 February 27, 2017 $ 0.19 6,984 March 15, 2017 March 30, 2017 $ 0.19 6,983 April 17, 2017 April 28, 2017 $ 0.19 6,984 May 15, 2017 May 30, 2017 $ 0.19 6,984 June 15, 2017 June 29, 2017 $ 0.19 6,983 July 17, 2017 July 27, 2017 $ 0.19 7,839 August 15, 2017 August 28, 2017 $ 0.19 7,839 September 15, 2017 September 28, 2017 $ 0.19 7,870 October 16, 2017 October 27, 2017 $ 0.19 7,956 November 15, 2017 November 27, 2017 $ 0.19 7,957 December 15, 2017 December 28, 2017 $ 0.19 8,046 Total dividends paid $ 89,409 December 31, 2016 Record Date Payment Date Rate per common share Aggregate amount paid to holders of record January 15, 2016 January 27, 2016 $ 0.33 $ 12,131 February 13, 2016 February 26, 2016 $ 0.33 12,131 March 13, 2016 March 28, 2016 $ 0.33 12,131 April 15, 2016 April 27, 2016 $ 0.27 9,925 May 16, 2016 May 27, 2016 $ 0.22 8,087 June 15, 2016 June 29, 2016 $ 0.22 8,087 July 15, 2016 July 27, 2016 $ 0.22 8,087 August 15, 2016 August 29, 2016 $ 0.22 8,087 September 15, 2016 September 27, 2016 $ 0.22 8,087 October 14, 2016 October 27, 2016 $ 0.22 8,086 November 15, 2016 November 29, 2016 $ 0.22 8,086 December 16, 2016 December 27, 2016 $ 0.22 8,086 Total dividends paid $ 111,011 December 31, 2015 Record Date Payment Date Rate per common share Aggregate amount paid to holders of record January 15, 2015 January 27, 2015 $ 0.32 $ 14,168 February 13, 2015 February 27, 2015 $ 0.32 14,169 March 13, 2015 March 27, 2015 $ 0.32 14,149 April 15, 2015 April 27, 2015 $ 0.32 14,133 May 15, 2015 May 27, 2015 $ 0.32 14,089 June 15, 2015 June 29, 2015 $ 0.32 14,045 July 15, 2015 July 27, 2015 $ 0.32 14,045 August 17, 2015 August 27, 2015 $ 0.33 14,477 September 15, 2015 September 28, 2015 $ 0.33 14,394 October 15, 2015 October 27, 2015 $ 0.33 13,438 November 16, 2015 November 27, 2015 $ 0.33 13,176 December 16, 2015 December 30, 2015 $ 0.33 12,859 Total dividends paid $ 167,142 The following tables present our Series A Preferred Stock dividend transactions for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . December 31, 2017 Record Date Payment Date Rate per Series A Preferred Share Aggregate amount paid to holders of record January 15, 2017 January 27, 2017 $ 0.17 $ 374.8 February 15, 2017 February 27, 2017 $ 0.17 374.8 March 15, 2017 March 27, 2017 $ 0.17 374.8 April 15, 2017 April 27, 2017 $ 0.17 374.8 May 15, 2017 May 30, 2017 $ 0.17 374.8 June 15, 2017 June 27, 2017 $ 0.17 374.8 July 15, 2017 July 27, 2017 $ 0.17 374.8 August 15, 2017 August 28, 2017 $ 0.17 374.8 September 15, 2017 September 27, 2017 $ 0.17 374.8 October 15, 2017 October 27, 2017 $ 0.17 374.8 November 15, 2017 November 27, 2017 $ 0.17 374.8 December 15, 2017 December 27, 2017 $ 0.17 374.8 Total dividends paid $ 4,497.6 December 31, 2016 Record Date Payment Date Rate per Series A Preferred Share Aggregate amount paid to holders of record January 15, 2016 January 27, 2016 $ 0.17 $ 374.8 February 15, 2016 February 26, 2016 $ 0.17 374.8 March 15, 2016 March 28, 2016 $ 0.17 374.8 April 15, 2016 April 27, 2016 $ 0.17 374.8 May 15, 2016 May 27, 2016 $ 0.17 374.8 June 15, 2016 June 29, 2016 $ 0.17 374.8 July 15, 2016 July 27, 2016 $ 0.17 374.8 August 15, 2016 August 29, 2016 $ 0.17 374.8 September 15, 2016 September 27, 2016 $ 0.17 374.8 October 15, 2016 October 27, 2016 $ 0.17 374.8 November 15, 2016 November 27, 2016 $ 0.17 374.8 December 15, 2016 December 28, 2016 $ 0.17 374.8 Total dividends paid $ 4,497.6 December 31, 2015 Record Date Payment Date Rate per Series A Preferred Share Aggregate amount paid to holders of record January 15, 2015 January 27, 2015 $ 0.17 $ 374.8 February 15, 2015 February 27, 2015 $ 0.17 374.8 March 15, 2015 March 27, 2015 $ 0.17 374.8 April 15, 2015 April 27, 2015 $ 0.17 374.8 May 15, 2015 May 27, 2015 $ 0.17 374.8 June 15, 2015 June 29, 2015 $ 0.17 374.8 July 15, 2015 July 27, 2015 $ 0.17 374.8 August 15, 2015 August 27, 2015 $ 0.17 374.8 September 15, 2015 September 28, 2015 $ 0.17 374.8 October 15, 2015 October 27, 2015 $ 0.17 374.8 November 15, 2015 November 27, 2015 $ 0.17 374.8 December 15, 2015 December 28, 2015 $ 0.17 374.8 Total dividends paid $ 4,497.6 The following tables present our Series B Preferred Stock dividend transactions for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . December 31, 2017 Record Date Payment Date Rate per Series B Preferred Share Aggregate amount paid to holders of record January 15, 2017 January 27, 2017 $ 0.16 $ 927 February 15, 2017 February 27, 2017 $ 0.16 927 March 15, 2017 March 27, 2017 $ 0.16 927 April 15, 2017 April 27, 2017 $ 0.16 927 May 15, 2017 May 30, 2017 $ 0.16 927 June 15, 2017 June 27, 2017 $ 0.16 927 July 15, 2017 July 27, 2017 $ 0.16 927 August 15, 2017 August 28, 2017 $ 0.16 927 September 15, 2017 September 27, 2017 $ 0.16 962 October 15, 2017 October 27, 2017 $ 0.16 987 November 15, 2017 November 27, 2017 $ 0.16 998 December 15, 2017 December 27, 2017 $ 0.16 1,019 Total dividends paid $ 11,382 December 31, 2016 Record Date Payment Date Rate per Series B Preferred Share Aggregate amount paid to holders of record January 15, 2016 January 27, 2016 $ 0.16 $ 927 February 15, 2016 February 26, 2016 $ 0.16 927 March 15, 2016 March 28, 2016 $ 0.16 927 April 15, 2016 April 27, 2016 $ 0.16 927 May 15, 2016 May 27, 2016 $ 0.16 927 June 15, 2016 June 29, 2016 $ 0.16 927 July 15, 2016 July 27, 2016 $ 0.16 927 August 15, 2016 August 29, 2016 $ 0.16 927 September 15, 2016 September 27, 2016 $ 0.16 927 October 15, 2016 October 27, 2006 $ 0.16 927 November 15, 2016 November 27, 2016 $ 0.16 927 December 15, 2016 December 28, 2016 $ 0.16 927 Total dividends paid $ 11,124 December 31, 2015 Record Date Payment Date Rate per Series B Preferred Share Aggregate amount paid to holders of record January 15, 2015 January 27, 2015 $ 0.16 $ 927 February 15, 2015 February 27, 2015 $ 0.16 927 March 15, 2015 March 27, 2015 $ 0.16 927 April 15, 2015 April 27, 2015 $ 0.16 927 May 15, 2015 May 27, 2015 $ 0.16 927 June 15, 2015 June 29, 2015 $ 0.16 927 July 15, 2015 July 27, 2015 $ 0.16 927 August 15, 2015 August 27, 2015 $ 0.16 927 September 15, 2015 September 28, 2015 $ 0.16 927 October 15, 2015 October 27, 2015 $ 0.16 927 November 15, 2015 November 27, 2015 $ 0.16 927 December 15, 2015 December 28, 2015 $ 0.16 927 Total dividends paid $ 11,124

Net Income (Loss) per Common 35

Net Income (Loss) per Common Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares	The following table presents a reconciliation of net income (loss) and the shares used in calculating weighted average basic and diluted earnings per common share for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . For the Years Ended December 31, 2017 December 31, 2016 December 31, 2015 Net Income (Loss) $ 181,154 $ (45,517 ) $ (31,205 ) Less: Preferred dividends (15,880 ) (15,622 ) (15,622 ) Net Income (Loss) available (related) to common stockholders $ 165,274 $ (61,139 ) $ (46,827 ) Weighted average common shares outstanding – basic 39,170 36,698 42,780 Add: Effect of dilutive non-vested awards, assumed vested 472 — — Weighted average common shares outstanding – diluted 39,642 36,698 42,780

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Schedule of Effective Income Tax Rate Reconciliation	The following table reconciles our GAAP net income (loss) to estimated REIT taxable income for the years ended December 31, 2017 , December 31, 2016 and December 31, 2015 . For the Years Ended December 31, 2017 December 31, 2016 December 31, 2015 GAAP net income (loss) $ 181,154 $ (45,517 ) $ (31,205 ) Book to tax differences: Credit Risk and Non-Agency Securities (68,505 ) (60,914 ) — Interest-Only Securities 1,216 (7,818 ) — Changes in interest rate contracts (49,930 ) 179,979 177,565 Losses on Security Sales 8,486 18,211 11,546 Other than temporary loss on Agency Securities 13,707 6,540 — Amortization of deferred hedging costs (59,930 ) (47,952 ) (13,731 ) Premium amortization expense on Agency Securities (468 ) — — Bargain purchase price on acquisition of JAVELIN — (6,484 ) — Other 15 19 17 Estimated taxable income $ 25,745 $ 36,064 $ 144,192
Schedule of Tax Credit Carryforwards	Net capital losses realized Amount Available to offset capital gains though 2013 (579,322 ) 2018 2014 (341,850 ) 2019 2015 (5,182 ) 2020 2016 (31,204 ) 2021

Acquisition of JAVELIN Mortga37

Acquisition of JAVELIN Mortgage Investment Corp. (Tables)	12 Months Ended
	Dec. 31, 2017
Business Combinations [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the consideration paid for JAVELIN and the amounts of the assets acquired and liabilities assumed recognized at the acquisition date, as well as the fair value at the acquisition date (amounts in millions): Consideration: Cash $ 85.2 Fair value of consideration transferred $ 85.2 Acquisition related costs (included in professional fees and other expenses) $ 2.5 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash $ 12.0 Cash collateral 24.6 Agency Securities 440.7 Credit Risk and Non-Agency Securities 223.2 Accrued interest receivable 1.4 Prepaid and other assets 5.4 Repurchase agreements (589.6 ) Derivatives (17.5 ) Accrued interest payable (0.9 ) Accounts payable and other accrued expenses (7.6 ) Total identifiable net assets $ 91.7 Bargain purchase price (6.5 ) Total $ 85.2

Quarterly Financial Data (una38

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following tables are a comparative breakdown of our unaudited quarterly financial results for the immediately preceding eight quarters. Quarter Ended March 31, June 30, September 30, December 31, Agency Securities, net of amortization of premium and fees (2) $ 44,081 $ 44,937 $ 52,292 54,991 Credit Risk and Non-Agency Securities, including discount accretion 13,898 14,514 13,973 13,584 Interest-Only Securities 603 577 516 467 Interest expense- repurchase agreements (18,064 ) (20,516 ) (27,137 ) (28,841 ) Net Interest Income $ 40,518 $ 39,512 $ 39,644 40,201 Realized gain (loss) on sale of Agency Securities (reclassified from Other comprehensive income (loss)) (11,154 ) (460 ) 891 2,237 Other than temporary impairment of Agency Securities — (10,338 ) (72 ) (3,297 ) Gain on Credit Risk and Non-Agency Securities 24,284 30,211 (7,571 ) 18,748 Gain (Loss) on Interest-Only Securities (3,743 ) 1,286 (183 ) (326 ) Realized gain (loss) on derivatives (1) (12,249 ) 9,641 897 (20,964 ) Unrealized gain (loss) on derivatives 23,768 (30,789 ) 2,574 43,719 Expenses (2) (8,706 ) (9,364 ) (8,456 ) (9,305 ) Net Income (Loss) $ 52,718 $ 29,699 $ 27,724 71,013 Dividends declared on preferred stock (3,905 ) (3,905 ) (3,940 ) (4,130 ) Net Income (Loss) available (related) to common stockholders $ 48,813 $ 25,794 $ 23,784 $ 66,883 Net income (loss) available (related) per share to common stockholders – Basic $ 1.33 $ 0.70 $ 0.58 $ 1.60 Net income (loss) available (related) per share to common stockholders – Diluted $ 1.33 $ 0.70 $ 0.58 $ 1.58 Dividends declared per common share $ 0.57 $ 0.57 $ 0.57 $ 0.57 Weighted average common shares outstanding – Basic 36,724 36,782 41,288 41,857 Weighted average common shares outstanding – Diluted 36,748 36,798 41,296 42,329 (1) Interest expense related to our interest rate swap contracts is recorded in realized loss on derivatives on the consolidated statements of operations. Quarter Ended March 31, June 30, September 30, December 31, Agency Securities, net of amortization of premium and fees (2) $ 78,650 $ 55,539 $ 44,544 $ 47,063 Credit Risk and Non-Agency Securities, including discount accretion 327 9,853 12,969 13,424 Interest-Only Securities — 3 852 771 Interest expense- repurchase agreements (19,148 ) (18,276 ) (17,040 ) (18,643 ) Net Interest Income $ 59,829 $ 47,119 $ 41,325 $ 42,615 Realized gain (loss) on sale of Agency Securities (reclassified from Other comprehensive income (loss)) 1,891 14,625 2,421 (37,147 ) Other than temporary impairment of Agency Securities — — — (6,540 ) Gain on Credit Risk and Non-Agency Securities 4,122 10,151 39,522 5,325 Gain (Loss) on Interest-Only Securities — (1,243 ) (1,105 ) 8,778 Bargain purchase price on acquisition of JAVELIN — 6,484 — — Realized gain (loss) on derivatives (1) (246,105 ) (112,515 ) 19,816 (113,594 ) Unrealized gain (loss) on derivatives (89,058 ) 66,141 25,824 203,305 Expenses (2) (10,154 ) (9,587 ) (9,115 ) (8,647 ) Net Income (Loss) $ (279,475 ) $ 21,175 $ 118,688 $ 94,095 Dividends declared on preferred stock (3,905 ) (3,905 ) (3,905 ) (3,906 ) Net Income (Loss) available (related) to common stockholders $ (283,380 ) $ 17,270 $ 114,783 $ 90,189 Net income (loss) available (related) per share to common stockholders – Basic $ (7.73 ) $ 0.47 $ 3.13 $ 2.46 Net income (loss) available (related) per share to common stockholders – Diluted $ (7.73 ) $ 0.47 $ 3.12 $ 2.45 Dividends declared per common share $ 0.99 $ 0.71 $ 0.66 $ 0.66 Weighted average common shares outstanding – Basic 36,683 36,693 36,703 36,713 Weighted average common shares outstanding – Diluted 36,683 36,748 36,746 36,745 (1) Interest expense related to our interest rate swap contracts is recorded in realized loss on derivatives on the consolidated statements of operations. (2) Certain amounts included in other expenses in the first and second quarters of 2016 have been reclassified to Interest Income Agency Securities.

Fair Value of Financial Instr39

Fair Value of Financial Instruments - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017dealer
Fair Value Disclosures [Abstract]
Number of dealers received quotes from	3

Fair Value of Financial Instr40

Fair Value of Financial Instruments - Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets at Fair Value:
Derivatives, at fair value	$ 37,211	$ 9,837
Liabilities at Fair Value:
Derivatives, at fair value	7,948	49,655
Fair Value, Measurements, Recurring
Assets at Fair Value:
Agency Securities, available for sale	7,478,966	6,511,164
Derivatives, at fair value	37,211	9,837
Liabilities at Fair Value:
Derivatives, at fair value	7,948	49,655
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets at Fair Value:
Agency Securities, available for sale	0	0
Derivatives, at fair value	0	0
Liabilities at Fair Value:
Derivatives, at fair value	0	0
Fair Value, Measurements, Recurring | Significant Observable Inputs (Level 2)
Assets at Fair Value:
Agency Securities, available for sale	7,478,966	6,511,164
Derivatives, at fair value	37,211	9,837
Liabilities at Fair Value:
Derivatives, at fair value	7,948	49,655
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets at Fair Value:
Agency Securities, available for sale	0	0
Derivatives, at fair value	0	0
Liabilities at Fair Value:
Derivatives, at fair value	0	0
Credit Risk and Non-Agency Securities
Assets at Fair Value:
Securities, trading, at fair value	975,829	1,052,170
Credit Risk and Non-Agency Securities | Fair Value, Measurements, Recurring
Assets at Fair Value:
Securities, trading, at fair value	975,829	1,052,170
Credit Risk and Non-Agency Securities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets at Fair Value:
Securities, trading, at fair value	0	0
Credit Risk and Non-Agency Securities | Fair Value, Measurements, Recurring | Significant Observable Inputs (Level 2)
Assets at Fair Value:
Securities, trading, at fair value	975,829	0
Credit Risk and Non-Agency Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets at Fair Value:
Securities, trading, at fair value	0	1,052,170
Interest-Only Securities
Assets at Fair Value:
Securities, trading, at fair value	25,752	33,627
Interest-Only Securities | Fair Value, Measurements, Recurring
Assets at Fair Value:
Securities, trading, at fair value	25,752	33,627
Interest-Only Securities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets at Fair Value:
Securities, trading, at fair value	0	0
Interest-Only Securities | Fair Value, Measurements, Recurring | Significant Observable Inputs (Level 2)
Assets at Fair Value:
Securities, trading, at fair value	25,752	33,627
Interest-Only Securities | Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Assets at Fair Value:
Securities, trading, at fair value	$ 0	$ 0

Fair Value of Financial Instr41

Fair Value of Financial Instruments - Carrying Values and Fair Values of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Quoted Prices in Active Markets for Identical Assets (Level 1)
Financial Assets:
Cash	$ 265,232	$ 271,773
Cash collateral posted to counterparties	0	0
Accrued interest receivable	0	0
Subordinated loans due from BUCKLER Securities LLC	0
Financial Liabilities:
Repurchase agreements	0	0
Cash collateral posted by counterparties	0	0
Accrued interest payable- repurchase agreements	0	0
Significant Observable Inputs (Level 2)
Financial Assets:
Cash	0	0
Cash collateral posted to counterparties	17,162	79,471
Accrued interest receivable	22,165	18,452
Subordinated loans due from BUCKLER Securities LLC	105,000
Financial Liabilities:
Repurchase agreements	7,555,917	6,818,453
Cash collateral posted by counterparties	29,593	3,774
Accrued interest payable- repurchase agreements	6,452	6,934
Fair Value, Inputs, Level 3
Financial Assets:
Cash	0	0
Cash collateral posted to counterparties	0	0
Accrued interest receivable	0	0
Subordinated loans due from BUCKLER Securities LLC	0
Financial Liabilities:
Repurchase agreements	0	0
Cash collateral posted by counterparties	0	0
Accrued interest payable- repurchase agreements	0	0
Carrying Value
Financial Assets:
Cash	265,232	271,773
Cash collateral posted to counterparties	17,162	79,471
Accrued interest receivable	22,165	18,452
Subordinated loans due from BUCKLER Securities LLC	105,000
Financial Liabilities:
Repurchase agreements	7,555,917	6,818,453
Cash collateral posted by counterparties	29,593	3,774
Accrued interest payable- repurchase agreements	6,452	6,934
Fair Value
Financial Assets:
Cash	265,232	271,773
Cash collateral posted to counterparties	17,162	79,471
Accrued interest receivable	22,165	18,452
Subordinated loans due from BUCKLER Securities LLC	105,000
Financial Liabilities:
Repurchase agreements	7,555,917	6,818,453
Cash collateral posted by counterparties	29,593	3,774
Accrued interest payable- repurchase agreements	$ 6,452	$ 6,934

Fair Value of Financial Instr42

Fair Value of Financial Instruments - Summary of Changes in Level 3 Assets Measured on a Recurring Basis (Details) - Credit Risk and Non-Agency Securities - Fair Value, Inputs, Level 3 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of year	$ 1,052,170	$ 0
Credit Risk and Non-Agency Securities acquired in the acquisition of JAVELIN, at fair value	0	223,220
Purchases of Credit Risk and Non-Agency Securities, at cost	8,224	882,588
Principal repayments of Credit Risk and Non-Agency Securities	(135,617)	(53,033)
Proceeds from the sale of Credit Risk and Non-Agency Securities	(8,372)	(61,843)
Gain on Credit Risk and Non-Agency Securities	46,924	59,120
Accretion of net discount on Credit Risk and Non-Agency Securities	3,187	2,118
Level 3 transferred to Level 2	(966,516)	0
Balance, end of year	0	1,052,170
Gain on Credit Risk and Non-Agency Securities	$ 54,495	$ 59,120

Fair Value of Financial Instr43

Fair Value of Financial Instruments - Unobservable Level 3 Input (Details)	12 Months Ended
	Dec. 31, 2017
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default	0.00%
Loss severity (life)	0.00%
Discount rate	3.62%
Delinquency (life)	0.00%
Voluntary prepayments (life)	1.50%
Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default	2.15%
Loss severity (life)	29.01%
Discount rate	4.47%
Delinquency (life)	4.84%
Voluntary prepayments (life)	8.72%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cumulative default	55.49%
Loss severity (life)	68.40%
Discount rate	5.50%
Delinquency (life)	50.10%
Voluntary prepayments (life)	14.60%

Agency Securities, Available 44

Agency Securities, Available for Sale - Additional Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Other than temporary impairment of Agency Securities	$ 3,297,000	$ 72,000	$ 10,338,000	$ 0	$ 6,540,000	$ 0	$ 0	$ 0	$ 13,707,000	$ 6,540,000	$ 0
Available-for-sale securities fair value	7,478,966,000				6,511,164,000				7,478,966,000	6,511,164,000
Gross realized gains (losses) from sale proceeds									4,012,398,000	7,195,157,000	5,367,123,000
Realized gain (loss) on sale of Agency Securities	2,237,000	$ 891,000	$ (460,000)	$ (11,154,000)	(37,147,000)	$ 2,421,000	$ 14,625,000	$ 1,891,000	(8,486,000)	(18,211,000)	(11,546,000)
Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Other than temporary impairment of Agency Securities									13,707,000
Available-for-sale securities fair value	$ 795,724,000								795,724,000
3.0% 15-year Fixed Rate Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Other than temporary impairment of Agency Securities										6,540,000
Available-for-sale securities fair value					$ 785,285,000					$ 785,285,000
AFS securities interest rate										3.00%
AFS securities term (in years)										15 years
Agency Securities
Schedule of Available-for-sale Securities [Line Items]
Other than temporary impairment of Agency Securities									$ 0	$ 0	$ 0
Weighted average coupon rate	3.68%				3.52%				3.68%	3.52%
Portfolio Concentration Risk | Agency Securities | MBS
Schedule of Available-for-sale Securities [Line Items]
Percentage of portfolio invested in agency securities									88.20%	85.70%

Agency Securities, Available 45

Agency Securities, Available for Sale - Unrealized Gain or Loss Position and Components of Carrying Value of Available for Sale Agency Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 7,499,077	$ 6,540,298
Gross Unrealized Loss	(39,392)	(42,257)
Gross Unrealized Gain	19,281	13,123
Fair Value	$ 7,478,966	$ 6,511,164
Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	100.00%	100.00%
Fannie Mae
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 5,895,221	$ 5,780,352
Gross Unrealized Loss	(30,334)	(32,666)
Gross Unrealized Gain	18,255	10,973
Fair Value	$ 5,883,142	$ 5,758,659
Fannie Mae | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	78.67%	88.44%
Fannie Mae | ARMs & Hybrids
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 28,199	$ 38,140
Gross Unrealized Loss	(229)	(174)
Gross Unrealized Gain	112	303
Fair Value	$ 28,082	$ 38,269
Fannie Mae | ARMs & Hybrids | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.38%	0.60%
Fannie Mae | Multi-Family MBS
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,799,737	$ 1,439,126
Gross Unrealized Loss	(5,132)	(5,677)
Gross Unrealized Gain	16,950	8,324
Fair Value	$ 1,811,555	$ 1,441,773
Fannie Mae | Multi-Family MBS | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	24.22%	22.14%
Fannie Mae | 10 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 60,634	$ 93,440
Gross Unrealized Loss	(347)	(755)
Gross Unrealized Gain	137	335
Fair Value	$ 60,424	$ 93,020
Fannie Mae | 10 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.81%	1.43%
Fannie Mae | 15 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,028,797	$ 2,796,785
Gross Unrealized Loss	(4,955)	(10,424)
Gross Unrealized Gain	625	2,011
Fair Value	$ 1,024,467	$ 2,788,372
Fannie Mae | 15 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	13.70%	42.82%
Fannie Mae | 20 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 29,832	$ 338,017
Gross Unrealized Loss	(621)	(4,629)
Gross Unrealized Gain	0	0
Fair Value	$ 29,211	$ 333,388
Fannie Mae | 20 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.39%	5.12%
Fannie Mae | 25 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 9,367	$ 12,126
Gross Unrealized Loss	(140)	(105)
Gross Unrealized Gain	0	0
Fair Value	$ 9,227	$ 12,021
Fannie Mae | 25 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.12%	0.18%
Fannie Mae | 30 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 2,938,655	$ 1,062,718
Gross Unrealized Loss	(18,910)	(10,902)
Gross Unrealized Gain	431	0
Fair Value	$ 2,920,176	$ 1,051,816
Fannie Mae | 30 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	39.05%	16.15%
Freddie Mac
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,565,099	$ 713,565
Gross Unrealized Loss	(8,526)	(8,805)
Gross Unrealized Gain	1,015	2,134
Fair Value	$ 1,557,588	$ 706,894
Freddie Mac | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	20.82%	10.86%
Freddie Mac | 10 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 37,254	$ 48,030
Gross Unrealized Loss	(158)	(149)
Gross Unrealized Gain	228	501
Fair Value	$ 37,324	$ 48,382
Freddie Mac | 10 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.50%	0.75%
Freddie Mac | 15 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 354,878	$ 530,590
Gross Unrealized Loss	(211)	(5,876)
Gross Unrealized Gain	787	1,633
Fair Value	$ 355,454	$ 526,347
Freddie Mac | 15 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	4.75%	8.08%
Freddie Mac | 20 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 19,503
Gross Unrealized Loss		(410)
Gross Unrealized Gain		0
Fair Value		$ 19,093
Freddie Mac | 20 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk		0.29%
Freddie Mac | 25 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 41,383	$ 115,442
Gross Unrealized Loss	(857)	(2,370)
Gross Unrealized Gain	0	0
Fair Value	$ 40,526	$ 113,072
Freddie Mac | 25 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.54%	1.74%
Freddie Mac | 30 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,131,584
Gross Unrealized Loss	(7,300)
Gross Unrealized Gain	0
Fair Value	$ 1,124,284
Freddie Mac | 30 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	15.03%
Ginnie Mae
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 38,757	$ 46,381
Gross Unrealized Loss	(532)	(786)
Gross Unrealized Gain	11	16
Fair Value	$ 38,236	$ 45,611
Ginnie Mae | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.51%	0.70%
Ginnie Mae | ARMs & Hybrids
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 38,494	$ 46,092
Gross Unrealized Loss	(532)	(786)
Gross Unrealized Gain	4	3
Fair Value	$ 37,966	$ 45,309
Ginnie Mae | ARMs & Hybrids | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.51%	0.70%
Ginnie Mae | 10 Year Fixed
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 263	$ 289
Gross Unrealized Loss	0	0
Gross Unrealized Gain	7	13
Fair Value	$ 270	$ 302
Ginnie Mae | 10 Year Fixed | Portfolio Concentration Risk | Available-for-sale Securities
Schedule of Available-for-sale Securities [Line Items]
Percentage of concentration risk	0.00%	0.00%

Agency Securities, Available 46

Agency Securities, Available for Sale - Summary of Weighted Average Lives of Agency Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value
Less than one year	$ 0	$ 4
Greater than or equal to one year and less than three years	29,126	17,773
Greater than or equal to three years and less than five years	1,353,036	3,237,524
Greater than or equal to five years	6,096,804	3,255,863
Total Agency Securities	7,478,966	6,511,164
Amortized Cost
Less than one year	0	5
Greater than or equal to one year and less than three years	29,269	17,998
Greater than or equal to three years and less than five years	1,353,998	3,248,401
Greater than or equal to five years	6,115,810	3,273,894
Amortized Cost	$ 7,499,077	$ 6,540,298

Agency Securities, Available 47

Agency Securities, Available for Sale - Gross Unrealized Losses and Estimated Fair Value of Agency Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value
Less than 12 Months	$ 4,355,924	$ 4,069,170
12 Months or More	733,637	61,133
Total	5,089,561	4,130,303
Unrealized Losses
Less than 12 Months	(28,906)	(41,045)
12 Months or More	(10,486)	(1,212)
Total	$ (39,392)	$ (42,257)

Credit Risk and Non-Agency Se48

Credit Risk and Non-Agency Securities, Trading - Additional Information (Details) - Credit Risk and Non-Agency Securities - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Proceeds from sale of trading securities	$ 8,372	$ 61,843	$ 0
Gain on Credit Risk and Non-Agency Securities	$ 85	$ 333
Portfolio Concentration Risk | Credit Risk and Non-Agency Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Percentage of concentration risk	11.50%	13.90%

Credit Risk and Non-Agency Se49

Credit Risk and Non-Agency Securities, Trading - Carrying Value of Non-Agency Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Credit Risk Transfer
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 870,494	$ 821,343
Amortized Cost	753,422	764,982
Principal Amount	$ 764,172	$ 778,216
Weighted Average Coupon	6.05%	5.26%
NPL/RPL
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value		$ 122,802
Amortized Cost		121,869
Principal Amount		$ 122,561
Weighted Average Coupon		3.80%
Legacy Prime Fixed
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 16,778	$ 19,954
Amortized Cost	15,287	19,406
Principal Amount	$ 19,237	$ 24,409
Weighted Average Coupon	6.03%	6.03%
Legacy ALTA Fixed
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 54,727	$ 59,253
Amortized Cost	48,516	56,776
Principal Amount	$ 65,920	$ 76,151
Weighted Average Coupon	5.85%	5.85%
Legacy Prime Hybrid
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 10,469	$ 11,914
Amortized Cost	9,517	11,163
Principal Amount	$ 11,452	$ 13,641
Weighted Average Coupon	3.17%	2.72%
Legacy ALTA Hybrid
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 4,660	$ 6,039
Amortized Cost	3,895	5,669
Principal Amount	$ 4,901	$ 6,956
Weighted Average Coupon	3.47%	3.01%
New Issue Prime Fixed Non-Agency
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 18,701	$ 10,865
Amortized Cost	17,957	10,708
Principal Amount	$ 19,025	$ 11,324
Weighted Average Coupon	3.69%	3.66%
Credit Risk and Non-Agency Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Fair Value	$ 975,829	$ 1,052,170
Amortized Cost	848,594	990,573
Principal Amount	$ 884,707	$ 1,033,258
Weighted Average Coupon	5.95%	5.08%

Credit Risk and Non-Agency Se50

Credit Risk and Non-Agency Securities, Trading - Weighted Average Lives of Non-Agency Securities (Details) - Credit Risk and Non-Agency Securities - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value
Less than one year	$ 0	$ 0
Greater than or equal to one year and less than three years	0	122,802
Greater than or equal to three years and less than five years	169,189	94,839
Greater than or equal to five years	806,640	834,529
Total Credit Risk and Non-Agency Securities	975,829	1,052,170
Amortized Cost
Less than one year	0	0
Greater than or equal to one year and less than three years	0	121,869
Greater than or equal to three years and less than five years	149,436	88,750
Greater than or equal to five years	699,158	779,954
Total Credit Risk and Non-Agency Securities	$ 848,594	$ 990,573

Credit Risk and Non-Agency Se51

Credit Risk and Non-Agency Securities, Trading - Continuous Unrealized Loss Position (Details) - Credit Risk and Non-Agency Securities - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value
Less than 12 months, fair value	$ 0	$ 2,022
12 months or more, fair value	0	0
Total, fair value	0	2,022
Unrealized Loss
Less than 12 months, unrealized loss	0	(14)
12 months or more, unrealized loss	0	0
Total, unrealized loss	$ 0	$ (14)

Repurchase Agreements - Additio

Repurchase Agreements - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)counterparty	Dec. 31, 2016USD ($)counterparty
Concentration Risk [Line Items]
Number of counterparties with master repurchase agreements	46	42
Number of counterparties with repurchase agreements outstanding	32	25
Repurchase Agreement Borrowings | Counterparty Concentration Risk
Concentration Risk [Line Items]
Percentage of concentration risk	5.10%	60.00%
Repurchase Agreement Borrowings | Counterparty Concentration Risk | One Repurchase Agreement Counterparty
Concentration Risk [Line Items]
Number of counterparties	1
Repurchase Agreement Borrowings | Counterparty Concentration Risk | Nine Repurchase Agreement Counterparties
Concentration Risk [Line Items]
Number of counterparties		9
Minimum | Repurchase Agreement Borrowings | Counterparty Concentration Risk
Concentration Risk [Line Items]
Percentage of concentration risk	5.00%	5.00%
Maximum
Concentration Risk [Line Items]
Ratio of indebtedness to net capital	12
Maximum | Repurchase Agreement Borrowings | Counterparty Concentration Risk
Concentration Risk [Line Items]
Percentage of concentration risk	10.00%	10.00%
Carrying Value
Concentration Risk [Line Items]
Repurchase agreements | $	$ 7,555,917	$ 6,818,453
BUCKLER Securities, LLC | Repurchase Agreement Borrowings | Counterparty Concentration Risk
Concentration Risk [Line Items]
Percentage of concentration risk	38.43%
BUCKLER Securities, LLC | Stockholders' Equity, Total [Member] | Counterparty Concentration Risk
Concentration Risk [Line Items]
Percentage of concentration risk	9.00%
Maturity term	70 days

Repurchase Agreements - Contrac

Repurchase Agreements - Contractual Repricing, Master Repurchase Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 7,555,917	$ 6,818,453
Weighted Average Contractual Rate	1.71%	1.07%
Weighted average maturity	51 days	22 days
Haircut for repurchase agreements	6.39%	7.45%
Agency Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 6,793,481	$ 6,017,843
Weighted Average Contractual Rate	1.60%	0.92%
Weighted average maturity	55 days	22 days
Haircut for repurchase agreements	4.29%	4.70%
Credit Risk and Non-Agency Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 762,436	$ 778,015
Weighted Average Contractual Rate	2.67%	2.26%
Weighted average maturity	15 days	23 days
Haircut for repurchase agreements	21.68%	23.82%
US Treasury Securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements		$ 22,595
Weighted Average Contractual Rate		0.46%
Weighted average maturity		3 days
Haircut for repurchase agreements		1.11%

Repurchase Agreements - Repurch

Repurchase Agreements - Repurchase Agreements by Maturity Period (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 7,555,917	$ 6,818,453
Weighted Average Contractual Rate	1.71%	1.07%
Maturity up to 30 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 1,738,768	$ 5,082,076
Weighted Average Contractual Rate	2.08%	1.11%
Maturity 31 to 60 Days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 2,394,450	$ 1,699,197
Weighted Average Contractual Rate	1.59%	0.94%
Maturity 61 to 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 3,422,699	$ 37,180
Weighted Average Contractual Rate	1.61%	2.38%
Maturity over 90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase Agreements	$ 0	$ 0
Weighted Average Contractual Rate	0.00%	0.00%

Derivatives - Interest Rate Swa

Derivatives - Interest Rate Swap Contracts, Swaptions and Futures Contracts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Derivative [Line Items]
Notional Amount	$ 6,850,000	$ 7,075,000
Derivatives, at fair value	37,211	9,837
Liability Fair Value	$ (7,948)	(49,655)
Notional amount, becoming effective in next six months		$ 300,000
Interest Rate Swap, 0-12 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term	5 months	7 months
Weighted Average Rate	0.92%	0.54%
Notional Amount	$ 50,000	$ 200,000
Derivatives, at fair value	191	158
Liability Fair Value	$ 0	$ 0
Interest Rate Swap 13-24 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term	23 months	17 months
Weighted Average Rate	1.21%	0.92%
Notional Amount	$ 550,000	$ 50,000
Derivatives, at fair value	6,398	0
Liability Fair Value	$ 0	$ (117)
Interest Rate Swap 25-36 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term	30 months	35 months
Weighted Average Rate	1.48%	1.21%
Notional Amount	$ 675,000	$ 550,000
Derivatives, at fair value	5,495	1,547
Liability Fair Value	$ 0	$ 0
Interest Rate Swap 61-72 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term	65 months
Weighted Average Rate	1.97%
Notional Amount	$ 1,975,000
Derivatives, at fair value	11,624
Liability Fair Value	$ (250)
Interest Rate Swap 73-84 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term	79 months	77 months
Weighted Average Rate	1.89%	1.97%
Notional Amount	$ 575,000	$ 2,075,000
Derivatives, at fair value	3,306	3,690
Liability Fair Value	$ (1,885)	$ (10,767)
Interest Rate Swap 85-96 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term		84 months
Weighted Average Rate		1.97%
Notional Amount		$ 100,000
Derivatives, at fair value		0
Liability Fair Value		$ (1,242)
Interest Rate Swap 97-108 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term	107 months
Weighted Average Rate	1.93%
Notional Amount	$ 1,050,000
Derivatives, at fair value	9,263
Liability Fair Value	$ (10)
Interest Rate Swap 109-120 Months
Derivative [Line Items]
Weighted Average Remaining Swap / Option Term	114 months	119 months
Weighted Average Rate	2.10%	1.95%
Notional Amount	$ 375,000	$ 1,250,000
Derivatives, at fair value	0	2,378
Liability Fair Value	(3,545)	(2,278)
TBA Agency Securities
Derivative [Line Items]
Notional Amount	1,600,000	2,850,000
Derivatives, at fair value	934	2,064
Liability Fair Value	(2,258)	(35,251)
Implied cost basis	1,674,438	2,922,582
Implied market value	1,673,113	2,889,395
Interest rate swap contracts
Derivative [Line Items]
Derivatives, at fair value	36,277	7,773
Liability Fair Value	$ (5,690)	$ (14,404)
Minimum | Interest Rate Swap, 0-12 Months
Derivative [Line Items]
Derivative, remaining maturity	0 months	0 months
Minimum | Interest Rate Swap 13-24 Months
Derivative [Line Items]
Derivative, remaining maturity	13 months	13 months
Minimum | Interest Rate Swap 25-36 Months
Derivative [Line Items]
Derivative, remaining maturity	25 months	25 months
Minimum | Interest Rate Swap 61-72 Months
Derivative [Line Items]
Derivative, remaining maturity	61 months
Minimum | Interest Rate Swap 73-84 Months
Derivative [Line Items]
Derivative, remaining maturity	73 months	73 months
Minimum | Interest Rate Swap 85-96 Months
Derivative [Line Items]
Derivative, remaining maturity		85 months
Minimum | Interest Rate Swap 97-108 Months
Derivative [Line Items]
Derivative, remaining maturity	97 months
Minimum | Interest Rate Swap 109-120 Months
Derivative [Line Items]
Derivative, remaining maturity	109 months	109 months
Minimum | TBA Agency Securities
Derivative [Line Items]
Derivative, remaining maturity	0 months	0 months
Maximum | Interest Rate Swap, 0-12 Months
Derivative [Line Items]
Derivative, remaining maturity	12 months	12 months
Maximum | Interest Rate Swap 13-24 Months
Derivative [Line Items]
Derivative, remaining maturity	24 months	24 months
Maximum | Interest Rate Swap 25-36 Months
Derivative [Line Items]
Derivative, remaining maturity	36 months	36 months
Maximum | Interest Rate Swap 61-72 Months
Derivative [Line Items]
Derivative, remaining maturity	72 months
Maximum | Interest Rate Swap 73-84 Months
Derivative [Line Items]
Derivative, remaining maturity	84 months	84 months
Maximum | Interest Rate Swap 85-96 Months
Derivative [Line Items]
Derivative, remaining maturity		96 months
Maximum | Interest Rate Swap 97-108 Months
Derivative [Line Items]
Derivative, remaining maturity	108 months
Maximum | Interest Rate Swap 109-120 Months
Derivative [Line Items]
Derivative, remaining maturity	120 months	120 months
Maximum | TBA Agency Securities
Derivative [Line Items]
Derivative, remaining maturity	60 months	60 months

Derivatives - Offsetting Assets

Derivatives - Offsetting Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Offsetting Assets [Line Items]
Net Amounts of Assets Presented in the Consolidated Balance Sheet	$ 37,211	$ 9,837
Gross Amounts of Assets Presented in the Consolidated Balance Sheet	37,211	9,837
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Financial Instruments	(7,948)	(49,655)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Net Cash Collateral Held	(14,621)	57,234
Net Amount	14,642	17,416
Interest rate swap contracts
Offsetting Assets [Line Items]
Net Amounts of Assets Presented in the Consolidated Balance Sheet	36,277	7,773
Gross Amounts of Assets Presented in the Consolidated Balance Sheet	36,277	7,773
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Financial Instruments	(5,690)	(14,404)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Net Cash Collateral Held	(22,689)	19,395
Net Amount	7,898	12,764
TBA Agency Securities
Offsetting Assets [Line Items]
Net Amounts of Assets Presented in the Consolidated Balance Sheet	934	2,064
Gross Amounts of Assets Presented in the Consolidated Balance Sheet	934	2,064
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Financial Instruments	(2,258)	(35,251)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Net Cash Collateral Held	8,068	37,839
Net Amount	$ 6,744	$ 4,652

Derivatives - Offsetting Liabil

Derivatives - Offsetting Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheet	$ (7,948)	$ (49,655)
Gross Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheet	(7,948)	(49,655)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Financial Instruments	7,948	49,655
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Cash Collateral Posted	0	0
Net Amount	0	0
Interest rate swap contracts
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheet	(5,690)	(14,404)
Gross Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheet	(5,690)	(14,404)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Financial Instruments	5,690	14,404
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Cash Collateral Posted	0	0
Net Amount	0	0
TBA Agency Securities
Offsetting Liabilities [Line Items]
Net Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheet	(2,258)	(35,251)
Gross Amounts of Liabilities Presented in the Condensed Consolidated Balance Sheet	(2,258)	(35,251)
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Financial Instruments	2,258	35,251
Gross Amounts Not Offset in the Condensed Consolidated Balance Sheet, Cash Collateral Posted	0	0
Net Amount	$ 0	$ 0

Derivatives - Location and Info

Derivatives - Location and Information of Derivatives (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss)	$ (20,964)	$ 897	$ 9,641	$ (12,249)	$ (113,594)	$ 19,816	$ (112,515)	$ (246,105)	$ (22,675)	[1]	$ (452,398)	[1]	$ (107,070)	[1]
Unrealized gain (loss) on derivatives	$ 43,719	$ 2,574	$ (30,789)	$ 23,768	$ 203,305	$ 25,824	$ 66,141	$ (89,058)	39,272		206,212		(181,662)
Subtotal									16,597		(246,186)		(288,732)
Interest rate swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Subtotal									7,045		(227,818)		(295,640)
Interest rate swap contracts | Realized loss on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss)									990		(370,192)		(2,274)
Interest income									50,464		25,270		13,066
Interest expense									(83,797)		(90,978)		(123,929)
Interest rate swap contracts | Unrealized gain (loss) on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives									39,388		208,082		(182,503)
Futures Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Subtotal									0		0		(4)
Futures Contracts | Realized loss on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss)									0		0		(184)
Futures Contracts | Unrealized gain (loss) on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives									0		0		180
Basis swap contracts
Derivative Instruments, Gain (Loss) [Line Items]
Subtotal									0		308		542
Basis swap contracts | Realized loss on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss)									0		1,468		0
Interest income									0		2,617		803
Interest expense									0		(3,116)		(922)
Basis swap contracts | Unrealized gain (loss) on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives									0		(661)		661
TBA Agency Securities
Derivative Instruments, Gain (Loss) [Line Items]
Subtotal									9,552		(18,676)		6,370
TBA Agency Securities | Realized loss on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss)									9,668		(17,467)		6,370
TBA Agency Securities | Unrealized gain (loss) on derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss) on derivatives									$ (116)		$ (1,209)		$ 0
[1]	Interest expense related to our interest rate swap contracts is recorded as realized loss on derivatives on the consolidated statements of operations. For additional information, see Note 9 to the consolidated financial statements.

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Thousands	Apr. 25, 2016lawsuit	Apr. 24, 2016defendant	Mar. 01, 2016lawsuit	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Other Commitments [Line Items]
Monthly percentage of effective management fee percentage				8.33%
Gross equity raised | $				$ 2,618,020	$ 2,469,368	$ 2,507,505
Transactions Case
Other Commitments [Line Items]
Number of new claims filed			9
Number of defendants, current directors | defendant		8
Number of consolidated claims	1
ARRM
Other Commitments [Line Items]
Percentage of gross equity raised used in calculation of management fee up to 1 Billion				1.50%
Percentage of gross equity raised used in calculation of management fee in excess of 1 Billion				0.75%
Effective management fee				1.04%	1.05%	1.05%

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 08, 2014	May 07, 2014
Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonemployee services transaction, quarterly fee	$ 33
The 2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)				15,000,000	2,000,000
Common stock, shares authorized (in shares)	1,875,000
Compensation cost not yet recognized	$ 12,063
Share price (in dollars per share)	$ 25.56
Period for recognition for compensation cost not yet recognized	3 years 7 months 6 days
Restricted Stock | The 2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted/Awards issued upon stockholders' approval of Plan amendment (in shares)	472,000	0	0

Stock Based Compensation - Sche

Stock Based Compensation - Schedule of Restricted Stock Units (Details) - The 2009 Stock Incentive Plan - Restricted Stock - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Awards
Unvested RSU Awards Outstanding beginning of period (in shares)	32	78	132
Granted/Awards issued upon stockholders' approval of Plan amendment (in shares)	472	0	0
Vested (in shares)	(32)	(46)	(53)
Forfeited (in shares)	0	0	(1)
Unvested RSU Awards Outstanding end of period (in shares)	472	32	78
Weighted Average Grant Date Fair Value per Award
Unvested RSU Awards Outstanding beginning of period (in dollars per share)	$ 39.80	$ 48.85	$ 51.76
Granted/Awards issued upon stockholders' approval of Plan amendment (in dollars per share)	24.82	0	0
Vested (in dollars per share)	39.80	56.14	56.40
Forfeited (in dollars per share)	0	0	58.90
Unvested RSU Awards Outstanding end of period (in dollars per share)	$ 24.82	$ 39.80	$ 48.85

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) $ / shares in Units, $ in Thousands	Jul. 31, 2015	Dec. 31, 2017USD ($)director$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares	Oct. 02, 2017$ / sharesshares	Aug. 30, 2017shares
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		50,000,000	50,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Preferred stock, undesignated shares authorized (in shares)		32,740,000
Common stock, shares outstanding (in shares)		41,877,000	36,723,000
Common stock, shares authorized (in shares)		125,000,000	125,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Common stock, shares issued (in shares)		41,877,000	36,723,000
Remaining shares authorized to be repurchased (in shares)		1,874,000	1,874,000
Common Stock
Class of Stock [Line Items]
Reverse stock split, conversion ratio, authorized	0.125
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		9,610,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Preferred stock, dividend rate		8.25%	8.25%
Preferred stock, shares issued (in shares)		2,181,000	2,181,000
Preferred stock, shares outstanding (in shares)		2,181,000	2,181,000
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares		$ 25	$ 25
Preferred stock, aggregate liquidation preference | $		$ 54,514	$ 54,514
Preferred stock, designated but unissued shares authorized (in shares)		7,429,000
Preferred stock, period stock receives voting rights if dividends are not paid (in months)		18 months
Number of additional directors elected | director		2
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)		7,650,000			2,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001
Preferred stock, dividend rate		7.875%	7.875%
Preferred stock, shares issued (in shares)		6,262,000	5,650,000
Preferred stock, shares outstanding (in shares)		6,262,000	5,650,000
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares		$ 25	$ 25
Preferred stock, aggregate liquidation preference | $		$ 156,560	$ 141,250
Preferred stock, designated but unissued shares authorized (in shares)		1,388,000
Preferred stock, period stock receives voting rights if dividends are not paid (in months)		18 months
Number of additional directors elected | director		2
At-The-Market Offering Program [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)				5,000
Common stock, par value (in dollars per share) | $ / shares				$ 0.001

Stockholders' Equity - Common S

Stockholders' Equity - Common Stock Repurchased (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)$ / sharesshares
Equity [Abstract]
Common stock repurchased (in shares) | shares	7,510
Common stock repurchased (in dollars per share) | $ / shares	$ 21.25
Common stock repurchased | $	$ 159,600

Stockholders' Equity - Equity T

Stockholders' Equity - Equity Transactions (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015
Series B Preferred Equity Distribution Agreement | Series B Preferred Stock
Class of Stock [Line Items]
Number of Shares (in shares)	612
Per Share price (in dollars per share)	$ 24.44
Net Proceeds	$ 14,968
Follow-On Public Offering
Class of Stock [Line Items]
Number of Shares (in shares)	4,500
Per Share price (in dollars per share)	$ 25.96
Net Proceeds	$ 116,693
Common Stock Dividend Reinvestment Program
Class of Stock [Line Items]
Number of Shares (in shares)	619	6
Per Share price (in dollars per share)	$ 26.44	$ 23.21
Net Proceeds	$ 16,500	$ 147

Stockholders' Equity - Dividend

Stockholders' Equity - Dividend Transactions (Details) - USD ($)	Dec. 28, 2017	Dec. 27, 2017	Nov. 27, 2017	Oct. 27, 2017	Sep. 28, 2017	Sep. 27, 2017	Aug. 28, 2017	Jul. 27, 2017	Jun. 29, 2017	Jun. 27, 2017	May 30, 2017	Apr. 28, 2017	Apr. 27, 2017	Mar. 30, 2017	Mar. 27, 2017	Feb. 27, 2017	Jan. 30, 2017	Jan. 27, 2017	Dec. 28, 2016	Dec. 27, 2016	Nov. 29, 2016	Nov. 27, 2016	Oct. 27, 2016	Sep. 27, 2016	Aug. 29, 2016	Jul. 27, 2016	Jun. 29, 2016	May 27, 2016	Apr. 27, 2016	Mar. 28, 2016	Feb. 26, 2016	Jan. 27, 2016	Dec. 30, 2015	Dec. 28, 2015	Nov. 27, 2015	Oct. 27, 2015	Sep. 28, 2015	Aug. 27, 2015	Jul. 27, 2015	Jun. 29, 2015	May 27, 2015	Apr. 27, 2015	Mar. 27, 2015	Feb. 27, 2015	Jan. 27, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock dividends cash paid (in dollars per share)	$ 0.19		$ 0.19	$ 0.19	$ 0.19		$ 0.19	$ 0.19	$ 0.19		$ 0.19	$ 0.19		$ 0.19		$ 0.19	$ 0.19			$ 0.22	$ 0.22		$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.27	$ 0.33	$ 0.33	$ 0.33	$ 0.33		$ 0.33	$ 0.33	$ 0.33	$ 0.33	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.32
Aggregate amount paid to holders of record (in dollars)	$ 8,046,000		$ 7,957,000	$ 7,956,000	$ 7,870,000		$ 7,839,000	$ 7,839,000	$ 6,983,000		$ 6,984,000	$ 6,984,000		$ 6,983,000		$ 6,984,000	$ 6,984,000			$ 8,086,000	$ 8,086,000		$ 8,086,000	$ 8,087,000	$ 8,087,000	$ 8,087,000	$ 8,087,000	$ 8,087,000	$ 9,925,000	$ 12,131,000	$ 12,131,000	$ 12,131,000	$ 12,859,000		$ 13,176,000	$ 13,438,000	$ 14,394,000	$ 14,477,000	$ 14,045,000	$ 14,045,000	$ 14,089,000	$ 14,133,000	$ 14,149,000	$ 14,169,000	$ 14,168,000	$ 89,409,000	$ 111,011,000	$ 167,142,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends cash paid (in dollars per share)		$ 0.17	$ 0.17	$ 0.17		$ 0.17	$ 0.17	$ 0.17		$ 0.17	$ 0.17		$ 0.17		$ 0.17	$ 0.17		$ 0.17	$ 0.17			$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17		$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17
Payments of dividends		$ 374,800	$ 374,800	$ 374,800		$ 374,800	$ 374,800	$ 374,800		$ 374,800	$ 374,800		$ 374,800		$ 374,800	$ 374,800		$ 374,800	$ 374,800			$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800		$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	4,497,600	4,497,600	4,498,000
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock dividends cash paid (in dollars per share)		$ 0.16	$ 0.16	$ 0.16		$ 0.16	$ 0.16	$ 0.16		$ 0.16	$ 0.16		$ 0.16		$ 0.16	$ 0.16		$ 0.16	$ 0.16			$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16		$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16
Payments of dividends		$ 1,019,000	$ 998,000	$ 987,000		$ 962,000	$ 927,000	$ 927,000		$ 927,000	$ 927,000		$ 927,000		$ 927,000	$ 927,000		$ 927,000	$ 927,000			$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000		$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 11,382,000	$ 11,124,000	$ 11,124,000

Net Income (Loss) per Common 66

Net Income (Loss) per Common Share - Reconciliation of Net Income (Loss) and Shares Used in Calculating Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net Income (Loss)	$ 71,013	$ 27,724	$ 29,699	$ 52,718	$ 94,095	$ 118,688	$ 21,175	$ (279,475)	$ 181,154	$ (45,517)	$ (31,205)
Less: Preferred dividends	(4,130)	(3,940)	(3,905)	(3,905)	(3,906)	(3,905)	(3,905)	(3,905)	(15,880)	(15,622)	(15,622)
Net Income (Loss) available (related) to common stockholders	$ 66,883	$ 23,784	$ 25,794	$ 48,813	$ 90,189	$ 114,783	$ 17,270	$ (283,380)	$ 165,274	$ (61,139)	$ (46,827)
Weighted average common shares outstanding – basic (in shares)	41,857	41,288	36,782	36,724	36,713	36,703	36,693	36,683	39,170	36,698	42,780
Add: Effect of dilutive non-vested awards, assumed vested (in shares)									472	0	0
Weighted average common shares outstanding – diluted (in shares)	42,329	41,296	36,798	36,748	36,745	36,746	36,748	36,683	39,642	36,698	42,780

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of GAAP Net Income to Estimated REIT Taxable Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
GAAP net income (loss)	$ 71,013	$ 27,724	$ 29,699	$ 52,718	$ 94,095	$ 118,688	$ 21,175	$ (279,475)	$ 181,154	$ (45,517)	$ (31,205)
Book to tax differences:
Credit Risk and Non-Agency Securities									(68,505)	(60,914)	0
Interest-Only Securities									1,216	(7,818)	0
Changes in interest rate contracts									(49,930)	179,979	177,565
Losses on Security Sales									8,486	18,211	11,546
Other than temporary loss on Agency Securities									13,707	6,540	0
Amortization of deferred hedging costs									(59,930)	(47,952)	(13,731)
Premium amortization expense on Agency Securities									(468)	0	0
Bargain purchase price on acquisition of JAVELIN									0	(6,484)	0
Other									15	19	17
Estimated taxable income									$ 25,745	$ 36,064	$ 144,192

Income Taxes - Capital Gains (L

Income Taxes - Capital Gains (Losses) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Capital Loss Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward	$ (31,204)	$ (5,182)	$ (341,850)	$ (579,322)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Aggregate tax basis of stockholders' equity in excess of assets and liabilities	$ 69,175
Aggregate tax basis of stockholders' equity in excess of assets and liabilities (in dollars per share)	$ 1.65
Common stock, shares issued (in shares)	41,877	36,723
Payment of dividends	$ 105,289	$ 126,633	$ 182,764
Estimated REIT taxable Income	$ 25,745	$ 36,064	$ 144,192
Percent of dividends that represent nontaxable return of capital	88.95%	81.55%	22.88%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Management fees		$ 26,582,000	$ 26,070,000	$ 27,292,000
ARRM
Related Party Transaction [Line Items]
Annual management fee		$ 1
Period of written notice of termination		180 days
Management fees		$ 26,582,000	26,070,000	27,292,000
ARRM | Armour Management Agreement
Related Party Transaction [Line Items]
Automatic renewal period of management agreement		5 years
ARRM | Javelin Management Agreement
Related Party Transaction [Line Items]
Automatic renewal period of management agreement		1 year
Management agreement, term		1 year
ARRM | Other Expense
Related Party Transaction [Line Items]
Management fees		$ 764,000	1,950,000	1,921,000
ARRM | Stock Based Compensation Expense
Related Party Transaction [Line Items]
Management fees		339,000	470,000	$ 623,000
Javelin Mortgage Investment Corp. | Management Fee
Related Party Transaction [Line Items]
Management fees		1,718,000	$ 1,657,000
Due to related parties		0
BUCKLER Securities, LLC | Corporate Joint Venture
Related Party Transaction [Line Items]
Payments to acquire equity method investments	$ 352,000
Ownership percentage	10.00%
Equity method investments, value		$ 84,000
BUCKLER Securities, LLC | Corporate Joint Venture | Required Regulatory Capital Requirement of Related Party
Related Party Transaction [Line Items]
Loans receivable related parties	$ 105,000,000
Related party transaction, rate	0.00%
Interest expense, related party	$ 280,000
BUCKLER Securities, LLC | Corporate Joint Venture | BUCKLER Subordinated Loan Due April 25, 2020
Related Party Transaction [Line Items]
Loans receivable related parties	25,000,000
BUCKLER Securities, LLC | Corporate Joint Venture | BUCKLER Subordinated Loan Due August 31, 2020
Related Party Transaction [Line Items]
Loans receivable related parties	15,000,000
BUCKLER Securities, LLC | Corporate Joint Venture | BUCKLER Subordinated Loan Due August 31, 2019
Related Party Transaction [Line Items]
Loans receivable related parties	$ 65,000,000

Acquisition of JAVELIN Mortga71

Acquisition of JAVELIN Mortgage Investment Corp. (Details) - USD ($) $ in Thousands	Apr. 06, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Recognized amounts of identifiable assets acquired and liabilities assumed:
Bargain purchase price on acquisition of JAVELIN		$ 0	$ 0	$ (6,484)	$ 0	$ 0	$ (6,484)	$ 0
Management Agreement | ARRM
Recognized amounts of identifiable assets acquired and liabilities assumed:
Accounts payable and other accrued expenses	$ (3,375)
Javelin Mortgage Investment Corp.
Business Acquisition [Line Items]
Cash	85,200
Fair value of consideration transferred	85,200
Acquisition related costs (included in professional fees and other expenses)	2,500
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	12,000
Cash collateral	24,600
Agency Securities	440,700
Credit Risk and Non-Agency Securities	223,200
Accrued interest receivable	1,400
Prepaid and other assets	5,400
Repurchase agreements	(589,600)
Derivatives	(17,500)
Accrued interest payable	(900)
Accounts payable and other accrued expenses	(7,600)
Total identifiable net assets	91,700	$ 105,580				79,475	105,580
Bargain purchase price on acquisition of JAVELIN	$ (6,500)
Total interest income						10,784	13,986
Net income						$ (1,683)	$ 15,171

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, shares in Thousands	Jan. 29, 2018	Jan. 27, 2018	Dec. 28, 2017	Dec. 27, 2017	Nov. 27, 2017	Oct. 27, 2017	Sep. 28, 2017	Sep. 27, 2017	Aug. 28, 2017	Jul. 27, 2017	Jun. 29, 2017	Jun. 27, 2017	May 30, 2017	Apr. 28, 2017	Apr. 27, 2017	Mar. 30, 2017	Mar. 27, 2017	Feb. 27, 2017	Jan. 30, 2017	Jan. 27, 2017	Dec. 28, 2016	Dec. 27, 2016	Nov. 29, 2016	Nov. 27, 2016	Oct. 27, 2016	Sep. 27, 2016	Aug. 29, 2016	Jul. 27, 2016	Jun. 29, 2016	May 27, 2016	Apr. 27, 2016	Mar. 28, 2016	Feb. 26, 2016	Jan. 27, 2016	Dec. 30, 2015	Dec. 28, 2015	Nov. 27, 2015	Oct. 27, 2015	Sep. 28, 2015	Aug. 27, 2015	Jul. 27, 2015	Jun. 29, 2015	May 27, 2015	Apr. 27, 2015	Mar. 27, 2015	Feb. 27, 2015	Jan. 27, 2015	Jan. 26, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Common stock dividends cash paid (in dollars per share)			$ 0.19		$ 0.19	$ 0.19	$ 0.19		$ 0.19	$ 0.19	$ 0.19		$ 0.19	$ 0.19		$ 0.19		$ 0.19	$ 0.19			$ 0.22	$ 0.22		$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.22	$ 0.27	$ 0.33	$ 0.33	$ 0.33	$ 0.33		$ 0.33	$ 0.33	$ 0.33	$ 0.33	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.32
Aggregate amount paid to holders of record (in dollars)			$ 8,046,000		$ 7,957,000	$ 7,956,000	$ 7,870,000		$ 7,839,000	$ 7,839,000	$ 6,983,000		$ 6,984,000	$ 6,984,000		$ 6,983,000		$ 6,984,000	$ 6,984,000			$ 8,086,000	$ 8,086,000		$ 8,086,000	$ 8,087,000	$ 8,087,000	$ 8,087,000	$ 8,087,000	$ 8,087,000	$ 9,925,000	$ 12,131,000	$ 12,131,000	$ 12,131,000	$ 12,859,000		$ 13,176,000	$ 13,438,000	$ 14,394,000	$ 14,477,000	$ 14,045,000	$ 14,045,000	$ 14,089,000	$ 14,133,000	$ 14,149,000	$ 14,169,000	$ 14,168,000										$ 89,409,000	$ 111,011,000	$ 167,142,000
Dividends declared per common share (in dollars per share)																																																	$ 0.57	$ 0.57	$ 0.57	$ 0.57	$ 0.66	$ 0.66	$ 0.71	$ 0.99	$ 2.28	$ 3.02	$ 3.89
Series A Preferred Stock
Subsequent Event [Line Items]
Preferred stock dividends cash paid (in dollars per share)				$ 0.17	$ 0.17	$ 0.17		$ 0.17	$ 0.17	$ 0.17		$ 0.17	$ 0.17		$ 0.17		$ 0.17	$ 0.17		$ 0.17	$ 0.17			$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17		$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17	$ 0.17
Aggregate amount paid to holders of record (in dollars)				$ 374,800	$ 374,800	$ 374,800		$ 374,800	$ 374,800	$ 374,800		$ 374,800	$ 374,800		$ 374,800		$ 374,800	$ 374,800		$ 374,800	$ 374,800			$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800		$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800	$ 374,800										$ 4,497,600	$ 4,497,600	$ 4,498,000
Series B Preferred Stock
Subsequent Event [Line Items]
Issuance of Series B Preferred stock, net of expenses																																																									14,815,000	0	0
Preferred stock dividends cash paid (in dollars per share)				$ 0.16	$ 0.16	$ 0.16		$ 0.16	$ 0.16	$ 0.16		$ 0.16	$ 0.16		$ 0.16		$ 0.16	$ 0.16		$ 0.16	$ 0.16			$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16		$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16	$ 0.16
Aggregate amount paid to holders of record (in dollars)				$ 1,019,000	$ 998,000	$ 987,000		$ 962,000	$ 927,000	$ 927,000		$ 927,000	$ 927,000		$ 927,000		$ 927,000	$ 927,000		$ 927,000	$ 927,000			$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000		$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000	$ 927,000										$ 11,382,000	$ 11,124,000	$ 11,124,000
Subsequent Event
Subsequent Event [Line Items]
Common stock dividends cash paid (in dollars per share)	$ 0.19
Aggregate amount paid to holders of record (in dollars)	$ 8,046,000
Dividends declared per common share (in dollars per share)	$ 0.19
Subsequent Event | Series A Preferred Stock
Subsequent Event [Line Items]
Preferred stock dividends cash paid (in dollars per share)		$ 0.17
Aggregate amount paid to holders of record (in dollars)		$ 375,000
Rate per preferred share dividends declared (in dollars per share)		$ 0.17
Subsequent Event | Series B Preferred Stock
Subsequent Event [Line Items]
Issuance of Series B Preferred stock, net (in shares)																																																107
Issuance of Series B Preferred stock, net of expenses																																																$ 2,632,000
Preferred stock dividends cash paid (in dollars per share)		$ 0.16
Aggregate amount paid to holders of record (in dollars)		$ 1,039,000
Rate per preferred share dividends declared (in dollars per share)		$ 0.16

Quarterly Financial Data (una73

Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Condensed Income Statements, Captions [Line Items]
Agency Securities, net of amortization of premium and fees	$ 54,991	$ 52,292	$ 44,937	$ 44,081	$ 47,063	$ 44,544	$ 55,539	$ 78,650	$ 196,301		$ 225,796		$ 365,300
Interest expense- repurchase agreements	(28,841)	(27,137)	(20,516)	(18,064)	(18,643)	(17,040)	(18,276)	(19,148)	(94,558)		(73,107)		(59,278)
Net Interest Income	40,201	39,644	39,512	40,518	42,615	41,325	47,119	59,829	159,875		190,888		306,022
Realized loss on sale of Agency Securities (reclassified from Other comprehensive income (loss))	2,237	891	(460)	(11,154)	(37,147)	2,421	14,625	1,891	(8,486)		(18,211)		(11,546)
Other than temporary impairment of Agency Securities	(3,297)	(72)	(10,338)	0	(6,540)	0	0	0	(13,707)		(6,540)		0
Bargain purchase price on acquisition of JAVELIN					0	0	6,484	0	0		6,484		0
Realized gain (loss) on derivatives	(20,964)	897	9,641	(12,249)	(113,594)	19,816	(112,515)	(246,105)	(22,675)	[1]	(452,398)	[1]	(107,070)	[1]
Unrealized gain (loss) on derivatives	43,719	2,574	(30,789)	23,768	203,305	25,824	66,141	(89,058)	39,272		206,212		(181,662)
Expenses	(9,305)	(8,456)	(9,364)	(8,706)	(8,647)	(9,115)	(9,587)	(10,154)	(35,831)		(37,503)		(36,949)
Net Income (Loss)	71,013	27,724	29,699	52,718	94,095	118,688	21,175	(279,475)	181,154		(45,517)		(31,205)
Dividends on preferred stock	(4,130)	(3,940)	(3,905)	(3,905)	(3,906)	(3,905)	(3,905)	(3,905)	(15,880)		(15,622)		(15,622)
Net Income (Loss) available (related) to common stockholders	$ 66,883	$ 23,784	$ 25,794	$ 48,813	$ 90,189	$ 114,783	$ 17,270	$ (283,380)	$ 165,274		$ (61,139)		$ (46,827)
Net income (loss) available (related) per share to common stockholders - Basic (in dollars per share)	$ 1.60	$ 0.58	$ 0.70	$ 1.33	$ 2.46	$ 3.13	$ 0.47	$ (7.73)	$ 4.22		$ (1.67)		$ (1.09)
Net income (loss) available (related) per share to common stockholders - Diluted (in dollars per share)	1.58	0.58	0.70	1.33	2.45	3.12	0.47	(7.73)	4.17		(1.67)		(1.09)
Dividends declared per common share (in dollars per share)	$ 0.57	$ 0.57	$ 0.57	$ 0.57	$ 0.66	$ 0.66	$ 0.71	$ 0.99	$ 2.28		$ 3.02		$ 3.89
Weighted average common shares outstanding – basic (in shares)	41,857	41,288	36,782	36,724	36,713	36,703	36,693	36,683	39,170		36,698		42,780
Weighted average common shares outstanding - diluted (in shares)	42,329	41,296	36,798	36,748	36,745	36,746	36,748	36,683	39,642		36,698		42,780
Credit Risk and Non-Agency Securities
Condensed Income Statements, Captions [Line Items]
Trading securities, interest income	$ 13,584	$ 13,973	$ 14,514	$ 13,898	$ 13,424	$ 12,969	$ 9,853	$ 327	$ 55,969		$ 36,573		$ 0
Gain (loss) on trading securities	18,748	(7,571)	30,211	24,284	5,325	39,522	10,151	4,122	65,672		59,120		0
Interest-Only Securities
Condensed Income Statements, Captions [Line Items]
Trading securities, interest income	467	516	577	603	771	852	3	0	2,163		1,626		0
Gain (loss) on trading securities	$ (326)	$ (183)	$ 1,286	$ (3,743)	$ 8,778	$ (1,105)	$ (1,243)	$ 0	$ (2,966)		$ 6,431		$ 0
[1]	Interest expense related to our interest rate swap contracts is recorded as realized loss on derivatives on the consolidated statements of operations. For additional information, see Note 9 to the consolidated financial statements.