Arlington Asset Investment (AAIC) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document Information [Line Items]
Entity Registrant Name	Arlington Asset Investment Corp.
Entity Central Index Key	1209028
Current Fiscal Year End Date	-19
Entity Filer Category	Accelerated Filer
Trading Symbol	AI
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2015
Common Class A [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		22,862,075
Common Class B [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		104,716

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
ASSETS
Cash and cash equivalents	$15,315	$33,832
Receivables
Interest	11,269	10,701
Sold securities receivable	78,915	0
Other	528	1,138
Mortgage-backed securities, at fair value
Available-for-sale	241,045	267,477
Trading	3,687,736	3,414,300
Other investments	1,819	1,837
Derivative assets, at fair value	1,508	1,267
Deferred tax assets, net	113,276	122,365
Deposits	213,037	160,427
Prepaid expenses and other assets	2,169	1,145
Total assets	4,366,617	4,014,489
Liabilities:
Repurchase agreements	3,371,690	3,179,775
Interest payable	1,162	1,106
Accrued compensation and benefits	1,562	6,067
Dividend payable	21,574	20,195
Derivative liabilities, at fair value	175,793	124,308
Purchased securities payable	148,252	0
Accounts payable, accrued expenses and other liabilities	751	1,006
Long-term debt	75,300	40,000
Total liabilities	3,796,084	3,372,457
Commitments and contingencies
Equity:
Preferred stock, $0.01 par value, 25,000,000 shares authorized, none issued and outstanding	0	0
Additional paid-in capital	1,897,138	1,897,027
Accumulated other comprehensive income, net of taxes of $8,623 and $11,666, respectively	28,017	35,872
Accumulated deficit	-1,354,852	-1,291,097
Total equity	570,533	642,032
Total liabilities and equity	4,366,617	4,014,489
Common Class A [Member]
Equity:
Common stock	229	229
Common Class B [Member]
Equity:
Common stock	$1	$1

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Preferred stock, par value (in dollars per share)	$0.01	$0.01
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, issued (in shares)	0	0
Preferred stock, outstanding (in shares)	0	0
Accumulated other comprehensive income, taxes (in dollars)	$8,623	$11,666
Common Class A [Member]
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized (in shares)	450,000,000	450,000,000
Common stock, shares issued (in shares)	22,860,922	22,860,922
Common stock, shares outstanding (in shares)	22,860,922	22,860,922
Common Class B [Member]
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	105,869	105,869
Common stock, shares outstanding (in shares)	105,869	105,869

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest income	$36,964	$23,867
Interest expense
Interest on short-term debt	3,080	1,734
Interest on long-term debt	648	551
Total interest expense	3,728	2,285
Net interest income	33,236	21,582
Other loss, net
Investment loss, net	-59,368	-5,911
Other loss	-3	-3
Total other loss, net	-59,371	-5,914
Operating (loss) income before other expenses	-26,135	15,668
Other expenses
Compensation and benefits	2,412	2,961
Professional services	130	516
Insurance	105	105
Occupancy and equipment	116	99
Board of director fees	238	231
Other operating expenses	307	243
Total other expenses	3,308	4,155
(Loss) income before income taxes	-29,443	11,513
Income tax provision	12,742	4,480
Net (loss) income	-42,185	7,033
Basic (loss) earnings per share (in dollars per share)	($1.84)	$0.42
Diluted (loss) earnings per share (in dollars per share)	($1.84)	$0.41
Weighted-average shares outstanding (in thousands)
Basic (in shares)	22,973	16,808
Diluted (in shares)	22,973	17,081
Other comprehensive (loss) income, net of taxes
Unrealized (losses) gains for the period on available-for-sale securities (net of taxes of $(2,663) and $621, respectively)	-4,493	974
Reclassification:
Included in investment loss, net, in the statement of comprehensive income related to sales of available-for-sale securities (net of taxes of $(380) and $(1,379), respectively)	-3,362	-3,078
Comprehensive (loss) income	($50,040)	$4,929

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Unrealized (losses) gains for the period on available-for-sale securities, taxes	($2,663)	$621
Included in investment loss, net, in the statement of comprehensive income related to sales of available-for-sale securities, taxes	($380)	($1,379)

CONSOLIDATED_STATEMENTS_OF_CHA

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $)	Total	Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]
In Thousands, except Share data, unless otherwise specified		Common Class A [Member]	Common Class B [Member]
Balances at Dec. 31, 2013	$551,828	$160	$6	$1,727,398	$46,269	($1,222,005)
Balances (in shares) at Dec. 31, 2013		16,047,965	554,055
Net income/Loss	5,954	0	0	0	0	5,954
Conversion of Class B common stock to Class A common stock	0	5	-5	0	0	0
Conversion of Class B common stock to Class A common stock (in shares)		448,186	-448,186
Issuance of Class A common stock	166,883	64	0	166,819	0	0
Issuance of Class A common stock (in shares)		6,419,247	0
Forfeitures of Class A common stock	-1,478	0	0	-1,478	0	0
Forfeitures of Class A common stock (in shares)		-54,476	0
Amortization of Class A common stock issued as stock-based awards	3,813	0	0	3,813	0	0
Income tax benefit from stock-based compensation	475	0	0	475	0	0
Other comprehensive income
Net change in unrealized gain on available-for-sale investment securities, (net of taxes)	-10,397	0	0	0	-10,397	0
Dividends declared	-75,046	0	0	0	0	-75,046
Balances at Dec. 31, 2014	642,032	229	1	1,897,027	35,872	-1,291,097
Balances (in shares) at Dec. 31, 2014		22,860,922	105,869
Net income/Loss	-42,185	0	0	0	0	-42,185
Amortization of Class A common stock issued as stock-based awards	111	0	0	111	0	0
Other comprehensive income
Net change in unrealized gain on available-for-sale investment securities, (net of taxes)	-7,855	0	0	0	-7,855	0
Dividends declared	-21,570	0	0	0	0	-21,570
Balances at Mar. 31, 2015	$570,533	$229	$1	$1,897,138	$28,017	($1,354,852)
Balances (in shares) at Mar. 31, 2015		22,860,922	105,869

CONSOLIDATED_STATEMENTS_OF_CHA1

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Net change in unrealized gain on available-for-sale investment securities, taxes	($3,043)	($4,691)

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net (loss) income	($42,185)	$7,033
Adjustments to reconcile net (loss) income to net cash provided by operating activities
Net investment loss	59,368	5,911
Net discount accretion on mortgage-backed securities	-2,696	-3,317
Deferred tax provision	12,132	4,125
Other	111	630
Changes in operating assets
Interest receivable	-568	-701
Other receivables	610	197
Prepaid expenses and other assets	213	-1,733
Changes in operating liabilities
Accounts payable and other liabilities	-320	358
Accrued compensation and benefits	-4,505	-4,355
Net cash provided by operating activities	22,160	8,148
Cash flows from investing activities:
Purchases of trading mortgage-backed securities	-331,514	-254,986
Proceeds from sales of available-for-sale mortgage-backed securities	20,859	8,626
Proceeds from sales of trading mortgage-backed securities	51,751	0
Receipt of principal payments on available-for-sale mortgage-backed securities	796	1,001
Receipt of principal payments on trading mortgage-backed securities	88,969	33,808
Payments for derivatives and deposits, net	-77,485	-23,980
Other	39	16
Net cash used in investing activities	-246,585	-235,515
Cash flows from financing activities:
Proceeds from repurchase agreements, net	191,915	223,892
Proceeds from stock issuance, net	0	81,769
Proceeds from long-term debt issuance, net	34,188	0
Dividends paid	-20,195	-14,630
Net cash provided by financing activities	205,908	291,031
Net (decrease) increase in cash and cash equivalents	-18,517	63,664
Cash and cash equivalents, beginning of period	33,832	48,628
Cash and cash equivalents, end of period	15,315	112,292
Supplemental cash flow information
Cash payments for interest	3,636	2,303
Cash payments for taxes	$0	$399

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Note 1. Basis of Presentation:
	The consolidated financial statements of Arlington Asset Investment Corp. (“Arlington Asset”) and its consolidated subsidiaries (unless the context otherwise provides, collectively, the “Company”) have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and with the instructions to Form 10-Q. Therefore, they do not include all information required by GAAP for complete financial statements. The interim financial statements reflect all adjustments (consisting only of normal recurring adjustments) which are, in the opinion of management, necessary for a fair statement of the results for the periods presented. All significant intercompany accounts and transactions have been eliminated in consolidation. The results of operations for the three months ended March 31, 2015 and 2014 are not necessarily indicative of the operating results for the entire year or any other subsequent interim period. The Company’s unaudited consolidated financial statements and notes thereto should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.
	The preparation of the Company’s financial statements in conformity with GAAP requires the Company to make estimates and assumptions affecting the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Although the Company based the estimates and assumptions on historical experience, when available, market information, and on various other factors that the Company believes to be reasonable under the circumstances, management exercises significant judgment in the final determination of the estimates. Actual results may differ from these estimates.
	Certain amounts in the consolidated financial statements and notes for prior periods have been reclassified to conform to the current period presentation. These reclassifications had no effect on the results of operations of the Company.

Financial_Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Financial Instruments	Note 2. Financial Instruments:
	Fair Value of Financial Instruments
	The accounting principles related to fair value measurements define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date, not adjusted for transaction costs. Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) 820, Fair Value Measurements and Disclosures (“ASC 820”), establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value into three broad levels giving the highest priority to quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3) as described below:
		Level 1 Inputs  —	Unadjusted quoted prices in active markets for identical assets or liabilities that are accessible by the Company;
		Level 2 Inputs  —	Quoted prices in markets that are not active or financial instruments for which all significant inputs are observable, either directly or indirectly; and
		Level 3 Inputs —	Unobservable inputs for the asset or liability, including significant assumptions of the Company and other market participants.
	The Company determines fair values for the following assets and liabilities:
	Mortgage-backed securities, at fair value —
	Agency-backed MBS — The Company’s mortgage-backed securities (“MBS”), the principal and interest payments on which are guaranteed by the Federal National Mortgage Association (“Fannie Mae”) or the Federal Home Loan Mortgage Corporation (“Freddie Mac”) (collectively, “agency-backed MBS”), are generally classified within Level 2 of the fair value hierarchy as they are valued using inputs primarily from third-party pricing services as well as considering quoted market prices provided by a broker or dealer with reasonable levels of price transparency. In determining fair value, third party pricing sources use various valuation approaches including market and income approaches. The Company makes inquiries of the third party pricing sources to understand the significant inputs and assumptions they used to determine their prices. The Company reviews the various third party fair value estimates and performs procedures to validate their reasonableness, including comparison to recent trading activity for similar securities and management review for consistency with market conditions observed as of the measurement date.
	Private-label MBS — The Company classifies non-agency-backed, or private-label, MBS within Level 3 of the fair value hierarchy because they trade infrequently and, therefore, have little or no price transparency. In determining fair value, the Company primarily uses an income approach as well as market approaches. The Company utilizes present value techniques based on estimated cash flows of the instrument taking into consideration various assumptions derived by management based on their observations of assumptions used by market participants. These assumptions are corroborated by evidence such as historical data, risk characteristics, transactions in similar instruments, and completed or pending transactions, when available. The significant inputs in the Company’s valuation process include default rate, loss severity, prepayment rate and discount rate. In general, significant increases (decreases) in default rate, loss severity or discount rate, in isolation, would result in a significantly lower (higher) fair value measurement. However, significant increases (decreases) in prepayment rate may result in a significantly higher (lower) fair value measurement. It is difficult to generalize the interrelationships between these significant inputs as the actual results could differ considerably on an individual security basis. For example, an increase in the default rate may not increase the loss severity rate if actual losses are lower than the average. Also, changes in discount rates may be greatly influenced by market expectation at any given point based upon many variables not directly related to the MBS market. Therefore, each significant input is closely analyzed to ascertain the reasonableness for the Company’s valuation purposes.
	Establishing fair value is inherently subjective given the volatile and sometimes illiquid markets for these private-label MBS and requires management to make a number of assumptions, including assumptions about the future of interest rates, prepayment rates, discount rates, credit loss rates, and the timing of cash flows and credit losses. The assumptions the Company applies are specific to each security. Although the Company relies on its internal calculations to compute the fair value of these private-label MBS, the Company requests and considers indications of value from actual sales of private-label MBS to assist in the valuation process and calibrate the Company’s model.
	Other investments  — The Company’s other investments, which are classified within Level 3 of the fair value hierarchy, consist of investments in equity securities, investment funds and other MBS-related securities, such as interest-only MBS.
	Derivative instruments  — In the normal course of the Company’s operations, the Company is a party to various financial instruments that are accounted for as derivatives in accordance with ASC 815, Derivatives and Hedging (“ASC 815”). The derivative instruments that trade in active markets or exchanges are classified within Level 1 of the fair value hierarchy because they are valued using quoted market prices. Other derivative instruments are generally classified within Level 2 of the fair value hierarchy because they are valued using broker or dealer quotations, which are model-based calculations based on market-based inputs, including, but not limited to, contractual terms, market prices, yield curves, credit curves, measures of volatility, prepayment rates and correlations of such inputs.
	Other  — Cash and cash equivalents, interest receivable, deposits, other receivable, interest payable, accounts payable, accrued expenses and other liabilities are reflected in the consolidated balance sheets at their amortized cost (which approximates fair value because of the short term nature of these instruments) and classified within Level 1 of the fair value hierarchy, except for certain cash equivalents that are held in money market funds that are classified within Level 2 of the fair value hierarchy.
	Sold securities receivable, repurchase agreements and purchased securities payable are reflected in the consolidated balance sheets at the cost basis, which approximates fair value because of the short term nature of these instruments, and classified within Level 2 of the fair value hierarchy.
	Long-term debt represents remaining balances of trust preferred debt and senior debt issued by the Company. Trust preferred debt is classified within Level 3 of the fair value hierarchy as the fair value is determined after considering quoted market prices provided by a broker or dealer. The independent brokers or dealers providing market prices are those who make markets in or specialists with expertise in the valuation of these financial instruments. The Company’s senior debt, which is publicly traded on the New York Stock Exchange, is classified within Level 1 of the fair value hierarchy.
	The estimated fair values of the Company’s financial instruments are as follows:
			March 31, 2015						December 31, 2014
			Carrying Amount			Estimated			Carrying Amount			Estimated
						Fair Value						Fair Value
	Financial assets:
	Cash and cash equivalents		$	15,315		$	15,315		$	33,832		$	33,832
	Interest receivable			11,269			11,269			10,701			10,701
	Sold securities receivable			78,915			78,915			—			—
	Other receivables			528			528			1,138			1,138
	MBS:
	Agency-backed MBS			3,687,764			3,687,764			3,414,340			3,414,340
	Private-label MBS			241,017			241,017			267,437			267,437
	Derivative assets			1,508			1,508			1,267			1,267
	Other investments			1,819			1,819			1,837			1,837
	Deposits			213,037			213,037			160,427			160,427
	Financial liabilities:
	Repurchase agreements			3,371,690			3,371,690			3,179,775			3,179,775
	Interest payable			1,162			1,162			1,106			1,106
	Long-term debt			75,300			75,000			40,000			39,200
	Derivative liabilities			175,793			175,793			124,308			124,308
	Purchased securities payable			148,252			148,252			—			—
	Accounts payable, accrued expenses and other liabilities			751			751			1,006			1,006
	Fair Value Hierarchy
	The following tables set forth financial instruments accounted for under ASC 820 by level within the fair value hierarchy as of March 31, 2015 and December 31, 2014. As required by ASC 820, assets and liabilities that are measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement.
	Financial Instruments Measured at Fair Value on a Recurring Basis
			March 31, 2015
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading:
	Agency-backed MBS		$	3,687,736		$	—		$	3,687,736		$	—
	Available-for-sale:
	Agency-backed MBS			28			—			28			—
	Private-label MBS			241,017			—			—			241,017
	Total available-for-sale			241,045			—			28			241,017
	Total MBS			3,928,781			—			3,687,764			241,017
	Derivative assets, at fair value			1,508			—			1,508			—
	Derivative liabilities, at fair value			-175,793			-175,106			-687			—
	Interest-only MBS, at fair value			207			—			—			207
	Total		$	3,754,703		$	-175,106		$	3,688,585		$	241,224
			December 31, 2014
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading:
	Agency-backed MBS		$	3,414,300		$	—		$	3,414,300		$	—
	Available-for-sale:
	Agency-backed MBS			40			—			40			—
	Private-label MBS			267,437			—			—			267,437
	Total available-for-sale			267,477			—			40			267,437
Total MBS			3,681,777			—			3,414,340			267,437
Derivative assets, at fair value			1,267			751			516			—
Derivative liabilities, at fair value			-124,308			-124,308			—			—
Interest-only MBS, at fair value			212			—			—			212
Total		$	3,558,948		$	-123,557		$	3,414,856		$	267,649
There were no transfers of securities in or out of Levels 1, 2 or 3 during the three months ended March 31, 2015 or the year ended December 31, 2014.
Level 3 Financial Assets and Liabilities
Financial Instruments Measured at Fair Value on a Recurring Basis
The fair value of the Company’s Level 3, available-for-sale, private-label MBS was $241,017 and $267,437 as of March 31, 2015 and December 31, 2014, respectively. As of March 31, 2015 and December 31, 2014, the private-label MBS portfolio consists primarily of re-REMIC tranches in securitization trusts issued between 2005 and 2010. During 2014, the Company’s private-label MBS portfolio also included senior securities which represent interests in securitizations that have the first right to cash flows and absorb losses last. The re-REMIC securities represent interests in re-securitizations of senior MBS and pro-rata mezzanine securities. For re-REMIC securities, the cash flows from, and any credit losses absorbed by, the underlying MBS are allocated among the re-REMIC securities issued in the re-securitization transactions based on the re-REMIC structure. For example, prime and non-prime residential senior securities have been resecuritized to create a two-tranche structure with a re-REMIC senior security and a re-REMIC subordinated security. In these re-REMIC securities, all principal payments from the underlying securities are directed to the re-REMIC senior security until the face value is fully paid off. Thereafter, all principal payments are directed to the re-REMIC subordinated security. For pro-rata mezzanine securities, principal payments from the underlying MBS are typically allocated concurrently and proportionally to the mezzanine securities along with senior securities. The re-REMIC subordinated and mezzanine securities absorb credit losses, if any, first; however, these credit losses occur only when credit losses exceed the credit protection provided to the underlying securities. Re-REMIC and mezzanine securities receive interest while any face value is outstanding.
The Company’s private-label MBS were collateralized by residential prime and Alt-A mortgage loans and had the following weighted average characteristics, based on face value, as of the dates indicated:
		March 31, 2015			December 31, 2014
Original loan-to-value			67	%		68	%
Original FICO score			721			722
Three-month prepayment rate			11	%		11	%
Three-month loss severities			42	%		41	%
Weighted average coupon			2.8	%		2.96	%
The significant unobservable inputs used to develop the estimated cash flows and discount rates in the valuation models for the Company’s private-label MBS include the following weighted-averages, based on face value, as of the dates indicated:
		Private-label MBS
		March 31, 2015			December 31, 2014
Discount rate			5.47	%		5.55	%
Default rate			3.05	%		3.09	%
Loss severity rate			42.13	%		42.25	%
Prepayment rate			10.99	%		11.23	%
The ranges of the significant unobservable inputs for the valuation model were as follows as of the dates indicated:
		Private-label MBS
		March 31, 2015			December 31, 2014
Discount rate			5.15 – 10.00	%		5.15 – 10.00	%
Default rate			1.00 – 8.25	%		1.00 – 8.80	%
Loss severity rate			29.21 – 57.50	%		29.23 – 57.50	%
Prepayment rate			7.40 – 17.70	%		7.40 – 17.70	%
The tables below set forth a summary of changes in the fair value and gains and losses of the Company’s Level 3 financial assets and liabilities that are measured at fair value on a recurring basis for the three months ended March 31, 2015 and 2014.
		Three Months Ended March 31, 2015
		Senior			Re-REMIC			Total
		Securities			Securities
Beginning balance, January 1, 2015		$	—		$	267,437		$	267,437
Total net gains (losses)
Included in earnings			—			3,432			3,432
Included in other comprehensive income			—			-10,905			-10,905
Purchases			—			—			—
Sales			—			-20,859			-20,859
Payments, net			—			-3,131			-3,131
Accretion of discount			—			5,043			5,043
Ending balance, March 31, 2015		$	—		$	241,017		$	241,017
The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date		$	—		$	—		$	—
		Three Months Ended March 31, 2014
		Senior			Re-REMIC			Total
		Securities			Securities
Beginning balance, January 1, 2014		$	7,066		$	334,233		$	341,299
Total net gains (losses)
Included in earnings			1,684			3,083			4,767
Included in other comprehensive income			-1,654			-1,191			-2,845
Purchases			—			—			—
Sales			-7,107			-8,626			-15,733
Payments, net			-215			-4,577			-4,792
Accretion of discount			226			6,924			7,150
Ending balance, March 31, 2014		$	—		$	329,846		$	329,846
The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date		$	—		$	—		$	—
Gains and losses included in earnings for the three months ended March 31, 2015 and 2014 are reported in the following statement of comprehensive income line descriptions:
		Other Loss, Investment Loss, net
		Three Months Ended March 31,
		2015			2014
Total gains (losses) included in earnings for the period		$	3,432		$	4,767
Change in unrealized gains (losses) relating to Level 3 assets still held at reporting date		$	—		$	—
Level 3 Financial Instruments Measured at Fair Value on a Non-Recurring Basis
The Company also measures certain financial assets at fair value on a non-recurring basis. Adjustments to the fair value of these assets usually result from the application of lower-of-cost-or-market accounting or write-downs of individual assets due to impairments. Due to the nature of these financial assets, enterprise values are primarily used to value these financial assets. In determining the enterprise value, the Company analyzes various financial, performance and market factors to estimate fair value, including where applicable, market trading activity. As a result, these financial assets are classified within Level 3 of the fair value hierarchy. As of March 31, 2015 and December 31, 2014, these financial assets are classified within the other investments category and represent the Company’s interest in non-public equity securities and investment funds and are valued at $1,612 and $1,625, respectively. For the three months ended March 31, 2015 and March 31, 2014, there were no changes to the carrying value of these financial assets.
MBS, at Fair Value
MBS, at fair value(1)(2), consisted of the following as of the dates indicated:
		March 31, 2015												December 31, 2014
		Fair			Net			Percent of			Weighted		Weighted	Fair		Net		Percent of			Weighted		Weighted
		Value			Unamortized			Total			Average		Average	Value		Unamortized		Total			Average		Average
					Premium			Fair			Life		Rating (3)			Premium		Fair			Life		Rating (3)
					(Discount)			Value								(Discount)		Value
Trading:
Fannie Mae		$	2,214,210		$	—			56.36	%		7.5	AAA	$	2,064,465	$	—		56.07	%		8.1	AAA
Freddie Mac			1,473,526			—			37.51	%		7.5	AAA		1,349,835		—		36.66	%		8.2	AAA
Available-for-sale:
Fannie Mae			28			—			—			4.6	AAA		40		—		—			4.9	AAA
Private-label			241,017			-116,839			6.13	%		10.2	NR		267,437		-133,333		7.27	%		10.4	NR
		$	3,928,781		$	-116,839			100	%				$	3,681,777	$	-133,333		100	%
	-1	The Company’s MBS portfolio was primarily comprised of fixed-rate MBS at March 31, 2015 and December 31, 2014. The weighted-average interest rate of the MBS portfolio at March 31, 2015 and December 31, 2014 was 3.92% and 3.93%, respectively.
	-2	As of March 31, 2015 and December 31, 2014, the Company’s MBS investments with a fair value of $3,602,372 and $3,376,025, respectively, were pledged as collateral for repurchase agreements.
	-3	The securities issued by Fannie Mae and Freddie Mac are not rated by any rating agency; however, they are commonly thought of as having an implied rating of “AAA.” There is no assurance, particularly given the downgrade of the U.S. credit rating to “AA+” by Standard & Poor’s during the quarter ended September 30, 2011 and Fitch Ratings Inc.’s announcement on October 15, 2013 that it had placed the U.S. credit rating on negative watch, that these securities would receive such a rating if they were ever rated by a rating agency. The weighted-average rating of the Company’s private-label senior securities is calculated based on face value of the securities.
The Company has generally purchased private-label MBS at a discount to face value. The Company, at least on a quarterly basis, estimates the future expected cash flows based on the Company’s observation of current information and events and applies a number of assumptions related to prepayment rates, interest rates, default rates, loss severity rates, and the timing and amount of cash flows and credit losses. These assumptions are difficult to predict, as they are subject to uncertainties and contingencies related to future events that may impact the Company’s estimates and its interest income.
Interest income on the private-label MBS that were purchased at a discount to face value is recognized based on each security’s expected effective interest rate. At acquisition, the accretable yield is calculated as the difference between the undiscounted expected cash flows and the purchase price which is expected to be accreted into interest income over the remaining life of the security on a level-yield basis. The difference between the contractually required payments and the undiscounted expected cash flows represents the non-accretable difference. Based on actual payment activities and changes in estimates of undiscounted expected future cash flows, the accretable yield and the non-accretable difference can change over time. Significant increases in the amount or timing of undiscounted expected future cash flows are recognized prospectively as an adjustment to the accretable yield.
The following table presents the changes in the accretable yield on available-for-sale, private-label MBS for the three months ended March 31, 2015 and 2014:
		Three Months Ended March 31,
		2015			2014
Beginning balance		$	202,108		$	326,330
Accretion of discount			-5,043			-7,150
Reclassifications, net			-9,182			4,645
Sales			-12,585			-12,892
Ending balance		$	175,298		$	310,933
The Company did not acquire any available-for-sale, private-label MBS during the three months ended March 31, 2015 and 2014.
The Company’s available-for-sale MBS are carried at fair value in accordance with ASC 320, Debt and Equity Securities (“ASC 320”), with resulting unrealized gains and losses reflected as other comprehensive income or loss. Gross unrealized gains and losses on these securities were the following as of the dates indicated:
		March 31, 2015
		Amortized			Unrealized
		Cost/Cost
		Basis (1)
					Gains			Losses			Fair Value
Agency-backed MBS		$	25		$	3		$	—		$	28
Private-label MBS			204,389			36,633			-5			241,017
Total		$	204,414		$	36,636		$	-5		$	241,045
	-1	The amortized cost of MBS includes unamortized net discounts of $116,839 at March 31, 2015.
		December 31, 2014
		Amortized			Unrealized
		Cost/Cost
		Basis (1)
					Gains			Losses			Fair Value
Agency-backed MBS		$	36		$	4		$	—		$	40
Private-label MBS			219,904			47,533			—			267,437
Total		$	219,940		$	47,537		$	—		$	267,477
	-1	The amortized cost of MBS includes unamortized net discounts of $133,333 at December 31, 2014.
The Company recorded no other-than-temporary impairment charges on available-for-sale MBS during the three months ended March 31, 2015 and 2014. The following table presents a summary of cumulative other-than-temporary impairment charges recognized on the available-for-sale MBS held as of the dates indicated:
		Three Months Ended March 31,
		2015			2014
Cumulative other-than-temporary impairment, beginning balance		$	18,903		$	23,663
Decreases related to other-than-temporary impairments on sold securities			—			-2,636
Cumulative other-than-temporary impairment, ending balance		$	18,903		$	21,027
The following table presents the results of sales of MBS for the periods indicated:
		Three Months Ended March 31,
		2015						2014
		Agency-Backed			Private-Label			Agency-Backed			Private-Label
		MBS			MBS			MBS			MBS
Proceeds from sales		$	130,666		$	20,859		$	—		$	15,733
Gross gains			399			3,348			—			4,669
Gross losses			8			—			—			—
Other Investments
The Company’s other investments consisted of the following as of the dates indicated:
		March 31, 2015			December 31, 2014
Interest-only MBS		$	207		$	212
Non-public equity securities			975			975
Investment funds			637			650
Total other investments		$	1,819		$	1,837

Borrowings

Borrowings	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Borrowings	Note 3. Borrowings:
	Repurchase Agreements
	The Company has entered into repurchase agreements to fund its investments in MBS. Securities sold under agreements to repurchase, which are treated as financing transactions for financial reporting purposes, are collateralized by MBS and are carried at their contractual amounts, including accrued interest, as specified in the respective agreements. Under the repurchase agreements, the Company pledges its securities as collateral to secure the borrowing, which is equal in value to a specified percentage of the fair value of the pledged collateral, while the Company retains beneficial ownership of the pledged collateral. The counterparty to the repurchase agreements may require that the Company pledge additional securities or cash as additional collateral to secure borrowings when the value of the collateral declines.
	As of March 31, 2015 and December 31, 2014, the Company had no amount at risk with a single repurchase agreement counterparty or lender greater than 10% of equity. The following table provides information regarding the Company’s outstanding repurchase agreement borrowings as of March 31, 2015 and December 31, 2014:
			March 31, 2015			December 31, 2014
	Pledged with agency-backed MBS:
	Repurchase agreements outstanding		$	3,308,802		$	3,137,586
	Agency-backed MBS collateral, at fair value			3,495,969			3,300,383
	Net amount (1)			187,167			162,797
	Weighted-average rate			0.36	%		0.38	%
	Weighted-average term to maturity			14.0 days			14.0 days
	Pledged with private-label MBS:
	Repurchase agreements outstanding		$	62,888		$	42,189
	Private-label MBS collateral, at fair value			106,403			75,642
	Net amount (1)			43,515			33,453
	Weighted-average rate			2.03	%		1.98	%
	Weighted-average term to maturity			21.4 days			21.8 days
	Total MBS:
	Repurchase agreements outstanding		$	3,371,690		$	3,179,775
	MBS collateral, at fair value			3,602,372			3,376,025
	Net amount (1)			230,682			196,250
	Weighted-average rate			0.39	%		0.4	%
	Weighted-average term to maturity			14.1 days			14.1 days
		-1	Net amount represents the value of collateral in excess of corresponding repurchase obligation. The amount of collateral at-risk is limited to the outstanding repurchase obligation and not the entire collateral balance.
	The following table provides information regarding the Company’s outstanding repurchase agreement borrowings during the three months ended March 31, 2015 and 2014:
			March 31, 2015			March 31, 2014
	Weighted-average outstanding balance during the three months ended		$	3,219,172		$	1,680,941
	Weighted-average rate during the three months ended			0.38	%		0.41	%
	Long-Term Debt
	As of March 31, 2015 and December 31, 2014, the Company had $75,300 and $40,000, respectively, of outstanding long-term debentures. On March 18, 2015, the Company completed a public offering of $35,300 of its 6.75% Senior Notes due in 2025 and received net proceeds of $34,063 after payment of underwriting discounts and commissions and expenses. These Senior Notes will mature on March 15, 2025, and may be redeemed in whole or in part at any time and from time to time at the Company’s option on or after March 15, 2018, at a redemption price equal to the principal amount redeemed plus accrued and unpaid interest. The interest payments on these Senior Notes are payable quarterly in arrears on March 15, June 15, September 15 and December 15 of each year, beginning on June 15, 2015. The indenture governing these Senior Notes contains certain covenants, including limitations on the Company’s ability to merge or consolidate with other entities or sell or otherwise dispose of all or substantially all of the Company’s assets. The Senior Notes due 2025 and the Senior Notes due 2023 are publicly traded on the New York Stock Exchange under the ticker symbol “AIC” and “AIW”, respectively.
	The Company’s long-term debentures consisted of the following as of the dates indicated:
			March 31, 2015								December 31, 2014
			Senior			Senior			Trust		Senior		Trust
			Notes Due 2025			Notes Due 2023			Preferred Debt		Notes Due 2023		Preferred Debt
	Outstanding Principal			$35,300		$	25,000		$	15,000	$	25,000	$	15,000
	Annual Interest Rate			6.75%			6.63%			LIBOR +		6.63%		LIBOR +
										2.25 – 3.00%				2.25 – 3.00%
	Interest Payment Frequency			Quarterly			Quarterly			Quarterly		Quarterly		Quarterly
	Weighted-Average Interest Rate			6.75%			6.63%			3.00%		6.63%		2.98%
	Maturity			15-Mar-25			1-May-23			2033 – 2035		1-May-23		2033 – 2035
	Early Redemption Date			15-Mar-18			1-May-16			2008 – 2010		1-May-16		2008 – 2010

Derivative_Financial_Instrumen

Derivative Financial Instruments and Hedging Activities	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments and Hedging Activities	Note 4. Derivative Financial Instruments and Hedging Activities:
	In the normal course of its operations, the Company is a party to financial instruments that are accounted for as derivative financial instruments in accordance with ASC 815. These instruments may include Eurodollar futures, interest rate swap futures, U.S. Treasury futures contracts, interest rate swaps, put options and certain commitments to purchase and sell MBS. The exchange traded derivatives such as Eurodollar futures and swap futures are cash settled on a daily basis. The Company may be required to pledge collateral for margin requirements with third-party custodians in connection with certain derivative transactions. These transactions are not under master netting agreements. In addition, certain features of the securitization structures of the Company’s private-label MBS are considered derivatives under ASC 815. The Company determined that these embedded derivatives have de minimis value, if any.
	During the three months ended March 31, 2015 and 2014, the Company entered into various financial contracts to hedge certain MBS and related borrowings and other long-term debt. These financial contracts are not designated as hedges under ASC 815. The changes in fair value on these derivatives are recorded to net investment gain or loss in the statement of comprehensive income. For the three months ended March 31, 2015 and 2014, the Company recorded net losses of $76,119 and $23,480, respectively, on these derivatives. The Company held the following derivative instruments as of the dates indicated:
			March 31, 2015				December 31, 2014
			Notional		Fair Value		Notional		Fair Value
			Amount				Amount
	Eurodollar futures:
	Derivative assets		$	—	$	—	$	2,445,000	$	751
	Derivative liabilities			42,725,000		-112,816		38,645,000		-76,848
	Total Eurodollar futures(1)			42,725,000		-112,816		41,090,000		-76,097
	10-year swap futures:
	Derivative assets			—		—		—		—
	Derivative liabilities			845,000		-62,079		1,145,000		-47,460
	Total 10-year swap futures(2)			845,000		-62,079		1,145,000		-47,460
	10-year U.S. Treasury note futures(3)			50,000		-211		—		—
	Commitment to purchase MBS(4)			217,544		1,508		200,000		516
	Commitment to sell MBS(5)			100,000		-687		—		—
		-1	The $42,725,000 total notional amount of Eurodollar futures contracts as of March 31, 2015 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2015 and 2019. The maximum notional outstanding for any future quarterly period did not exceed $2,525,000 as of March 31, 2015 and $2,325,000 as of December 31, 2014. As of March 31, 2015, the Company maintained $136,051 as a deposit and margin against the open Eurodollar futures contracts.
		-2	The $845,000 represents the total notional amount of 10-year swap futures as of March 31, 2015, of which $480,000 of notional amount matures in June 2015 and $365,000 in notional amount matures in March 2024. As of March 31, 2015, the Company maintained $76,100 as a deposit and margin against the open 10-year swap futures contracts.
		-3	The $50,000 total notional amount of 10-year Treasury note futures as of March 31, 2015 represents the accumulation of 10-year Treasury note futures that mature in June 2015. As of March 31, 2015, the Company maintained $886 as a deposit and margin against the open 10-year Treasury note futures.
		-4	The total notional amount of commitment to purchase MBS represents forward commitments to purchase fixed-rate MBS securities.
		-5	The total notional amount of commitment to sell MBS represents forward commitments to sell fixed-rate MBS securities.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Note 5. Income Taxes:
	Arlington Asset is subject to taxation as a corporation under Subchapter C of the Internal Revenue Code of 1986, as amended (the “Code”). The Company’s consolidated subsidiary, Rosslyn REIT Trust (“Rosslyn REIT”), operates to qualify as a real estate investment trust (“REIT”) under the Code. The investments of Rosslyn REIT primarily consist of a portion of the Company’s private-label MBS portfolio. Arlington Asset owns all of the common shares of Rosslyn REIT and all of the preferred shares are owned by outside investors. Rosslyn REIT periodically distributes all of its income to its shareholders. The Company’s agency-backed MBS and remaining private label MBS investment portfolios are primarily held by Arlington Asset.
	The Company currently has net operating loss (“NOL”) and net capital loss (“NCL”) carry-forwards that can be applied against the Company’s current taxable ordinary income and net capital gains.
	As of March 31, 2015 and December 31, 2014, the Company had a net deferred tax asset of $113,276 and $122,365, respectively, net of a valuation allowance on NCL carry-forwards of $51,406 and $26,027, respectively. The Company continues to provide a valuation allowance against the portion of NCL carry-forwards for which the Company believes is more likely than not that the benefits will not be realized prior to expiration. The Company’s NCL carry-forwards expire in 2019, and any net capital loss generated in the current year will expire in 2020. During the three months ended March 31, 2015, the Company recorded an increase to its valuation allowance of $25,379 primarily due to realized and unrealized net capital losses generated during the period from certain of its derivative hedge instruments. The Company will continue to assess the need for a valuation allowance at each reporting date.
	As of March 31, 2015, the Company has assessed the need for recording a provision for any uncertain tax position and has made the determination that such provision is not necessary.
	The Company is subject to examination by the U.S. Internal Revenue Service (“IRS”) and state and local taxing jurisdictions where the Company has significant business operations. As of March 31, 2015, there are no on-going examinations.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Note 6. Earnings Per Share:
	Basic earnings per share includes no dilution and is computed by dividing net income or loss applicable to common stock by the weighted-average number of common shares outstanding for the respective period. Diluted earnings per share includes the impact of dilutive securities such as unvested shares of restricted stock and performance share units. The following tables present the computations of basic and diluted earnings per share for the periods indicated:
		Three Months Ended March 31,
		2015				2014
	(Shares in thousands)	Basic		Diluted		Basic		Diluted
	Weighted-average shares outstanding
	Common stock		22,973		22,973		16,808		16,808
	Performance share units and unvested restricted stock		—		—		—		273
	Weighted-average common and common equivalent shares outstanding		22,973		22,973		16,808		17,081
	Net (loss) income applicable to common stock	$	-42,185	$	-42,185	$	7,033	$	7,033
	Net (loss) income per common share	$	-1.84	$	-1.84	$	0.42	$	0.41
	The diluted earnings per share for the three months ended March 31, 2015 did not include the antidilutive effect of 123,242 unvested shares of restricted stock and performance share units.

Equity

Equity	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Equity	Note 7. Equity:
	Dividends
	Pursuant to the Company’s variable dividend policy, the Board of Directors evaluates dividends on a quarterly basis and, in its sole discretion, approves the payment of dividends. The Company’s dividend payments, if any, may vary significantly from quarter to quarter. The Board of Directors has approved and the Company has declared the following dividends to date in 2015:
	Quarter Ended	Dividend		Declaration Date		Record Date		Pay Date
		Amount
	31-Mar	$	0.875	10-Mar		31-Mar		30-Apr
	The Board of Directors approved and the Company declared and paid the following dividends for 2014:
	Quarter Ended	Dividend		Declaration Date			Record Date		Pay Date
		Amount
	31-Dec	$	0.875		18-Dec			31-Dec		30-Jan-15
	30-Sep		0.875		17-Sep			29-Sep		31-Oct
	30-Jun		0.875		11-Jun			30-Jun		31-Jul
	31-Mar		0.875		13-Mar			31-Mar		30-Apr

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Note 8. Recent Accounting Pronouncements:
	On April 7, 2015, the FASB issued Accounting Standards Update (“ASU”) No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”), which requires debt issuance costs to be presented in the balance sheet as a direct reduction from the associated debt liability. For public business entities, the standard is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted for financial statements that have not been previously issued. The new guidance will be applied on a retrospective basis. The Company is currently evaluating the impact of ASU 2015-03.
	On February 18, 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810) – Amendments to the Consolidation Analysis (“ASU 2015-02”), which makes targeted amendments to the current consolidation guidance and ends the deferral granted to investment companies from applying variable interest entity guidance. For public business entities, the standard is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact of ASU 2015-02.
	On January 9, 2015, the FASB issued ASU No. 2015-01, Extraordinary and Unusual Items (Subtopic 225-20) – Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items (“ASU 2015-01”), which eliminates from U.S. GAAP the concept of extraordinary items. The standard is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted provided that the guidance is applied from the beginning of the fiscal year of adoption. The Company does not believe the adoption of ASU 2015-01 will have a material impact on its consolidated financial statements.
	On May 28, 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard will be effective for the Company on January 1, 2017. Early application is not permitted. The Company is currently evaluating the impact of ASU 2014-09.
	On August 27, 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements — Going Concern (subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (“ASU 2014-15”), which is intended to define management’s responsibility to evaluate whether there is substantial doubt about the Company’s ability to continue as a going concern and to provide related footnote disclosures. This standard will be effective for the Company for the year ending on December 31, 2016. Early application is permitted. The Company is currently evaluating the impact of ASU 2014-15.

Revisions_to_Previously_Report

Revisions to Previously Reported Financial Statements	3 Months Ended
	Mar. 31, 2015
Accounting Changes and Error Corrections [Abstract]
Revisions to Previously Reported Financial Statements	Note 9. Revisions to Previously Reported Financial Statements:
	The Company concluded that the previously reported tax effect of the components of other comprehensive income (loss) was incorrect for the three months ended March 31, 2014. Although the error did not have an impact on the previously reported total other comprehensive income (loss), it did have an impact on the previously reported components of other comprehensive income (loss). Although the impact of this change was not material to the consolidated financial statements for the three months ended March 31, 2014, the Company has revised its previously reported consolidated financial statements for the three months ended March 31, 2014. The following table sets forth the affected line items within the Company’s previously reported consolidated financial statements for the three months ended March 31, 2014.
		Three Months Ended March 31, 2014
		As Previously Reported		Revision		As Revised
	Other comprehensive income (loss), net of taxes:
	Unrealized gains for the period on available-for-sale securities	$	2,215	$	-1,241	$	974
	Reclassification:
	Included in investment loss, net, in the statement of comprehensive income related to sales of available-for-sale securities		-4,319		1,241		-3,078
	Total other comprehensive loss	$	-2,104	$	—	$	-2,104
	During the preparation of the consolidated financial statements as of March 31, 2015, the Company concluded that the previously reported income tax provision (benefit) and the related income tax effect on other comprehensive income (loss) was incorrect for the fiscal years ended December 31, 2012 and 2013 with no impact on previously reported total comprehensive income. As a result of these errors, the Company also concluded that the previously reported accumulated other comprehensive income and accumulated deficit was incorrect as of the three fiscal years ended December 31, 2014 for the cumulative impact of the errors, however, with no impact on previously reported total equity. Although the impact of these changes were not material to the consolidated financial statements for the three fiscal years ended December 31, 2014, the Company has revised its previously reported accumulated other comprehensive income and accumulated deficit as of December 31, 2014 and 2013 to reflect the cumulative impact of the errors. The following tables set forth the affected line items within the Company’s previously reported consolidated balance sheets as of December 31, 2014 and 2013.
		As of December 31, 2014
		As Previously Reported		Revision		As Revised
	Accumulated other comprehensive income, net of taxes	$	42,793	$	-6,921	$	35,872
	Accumulated deficit	$	-1,298,018	$	6,921	$	-1,291,097
		As of December 31, 2013
		As Previously Reported		Revision		As Revised
	Accumulated other comprehensive income, net of taxes	$	53,190	$	-6,921	$	46,269
	Accumulated deficit	$	-1,228,926	$	6,921	$	-1,222,005

Financial_Instruments_Tables

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping [Table Text Block]	The estimated fair values of the Company’s financial instruments are as follows:
			March 31, 2015						December 31, 2014
			Carrying Amount			Estimated			Carrying Amount			Estimated
						Fair Value						Fair Value
	Financial assets:
	Cash and cash equivalents		$	15,315		$	15,315		$	33,832		$	33,832
	Interest receivable			11,269			11,269			10,701			10,701
	Sold securities receivable			78,915			78,915			—			—
	Other receivables			528			528			1,138			1,138
	MBS:
	Agency-backed MBS			3,687,764			3,687,764			3,414,340			3,414,340
	Private-label MBS			241,017			241,017			267,437			267,437
	Derivative assets			1,508			1,508			1,267			1,267
	Other investments			1,819			1,819			1,837			1,837
	Deposits			213,037			213,037			160,427			160,427
	Financial liabilities:
	Repurchase agreements			3,371,690			3,371,690			3,179,775			3,179,775
	Interest payable			1,162			1,162			1,106			1,106
	Long-term debt			75,300			75,000			40,000			39,200
	Derivative liabilities			175,793			175,793			124,308			124,308
	Purchased securities payable			148,252			148,252			—			—
	Accounts payable, accrued expenses and other liabilities			751			751			1,006			1,006
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]	Financial Instruments Measured at Fair Value on a Recurring Basis
			March 31, 2015
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading:
	Agency-backed MBS		$	3,687,736		$	—		$	3,687,736		$	—
	Available-for-sale:
	Agency-backed MBS			28			—			28			—
	Private-label MBS			241,017			—			—			241,017
	Total available-for-sale			241,045			—			28			241,017
	Total MBS			3,928,781			—			3,687,764			241,017
	Derivative assets, at fair value			1,508			—			1,508			—
	Derivative liabilities, at fair value			-175,793			-175,106			-687			—
	Interest-only MBS, at fair value			207			—			—			207
	Total		$	3,754,703		$	-175,106		$	3,688,585		$	241,224
			December 31, 2014
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading:
	Agency-backed MBS		$	3,414,300		$	—		$	3,414,300		$	—
	Available-for-sale:
	Agency-backed MBS			40			—			40			—
	Private-label MBS			267,437			—			—			267,437
	Total available-for-sale			267,477			—			40			267,437
	Total MBS			3,681,777			—			3,414,340			267,437
	Derivative assets, at fair value			1,267			751			516			—
	Derivative liabilities, at fair value			-124,308			-124,308			—			—
	Interest-only MBS, at fair value			212			—			—			212
	Total		$	3,558,948		$	-123,557		$	3,414,856		$	267,649
Weighted Average Underlying Loan Characteristics Private Label MBS [Table Text Block]	The Company’s private-label MBS were collateralized by residential prime and Alt-A mortgage loans and had the following weighted average characteristics, based on face value, as of the dates indicated:
			March 31, 2015			December 31, 2014
	Original loan-to-value			67	%		68	%
	Original FICO score			721			722
	Three-month prepayment rate			11	%		11	%
	Three-month loss severities			42	%		41	%
	Weighted average coupon			2.8	%		2.96	%
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	The significant unobservable inputs used to develop the estimated cash flows and discount rates in the valuation models for the Company’s private-label MBS include the following weighted-averages, based on face value, as of the dates indicated:
			Private-label MBS
			March 31, 2015			December 31, 2014
	Discount rate			5.47	%		5.55	%
	Default rate			3.05	%		3.09	%
	Loss severity rate			42.13	%		42.25	%
	Prepayment rate			10.99	%		11.23	%
	The ranges of the significant unobservable inputs for the valuation model were as follows as of the dates indicated:
			Private-label MBS
			March 31, 2015			December 31, 2014
	Discount rate			5.15 – 10.00	%		5.15 – 10.00	%
	Default rate			1.00 – 8.25	%		1.00 – 8.80	%
	Loss severity rate			29.21 – 57.50	%		29.23 – 57.50	%
	Prepayment rate			7.40 – 17.70	%		7.40 – 17.70	%
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block]	The tables below set forth a summary of changes in the fair value and gains and losses of the Company’s Level 3 financial assets and liabilities that are measured at fair value on a recurring basis for the three months ended March 31, 2015 and 2014.
			Three Months Ended March 31, 2015
			Senior			Re-REMIC			Total
			Securities			Securities
	Beginning balance, January 1, 2015		$	—		$	267,437		$	267,437
	Total net gains (losses)
	Included in earnings			—			3,432			3,432
	Included in other comprehensive income			—			-10,905			-10,905
	Purchases			—			—			—
	Sales			—			-20,859			-20,859
	Payments, net			—			-3,131			-3,131
	Accretion of discount			—			5,043			5,043
	Ending balance, March 31, 2015		$	—		$	241,017		$	241,017
	The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date		$	—		$	—		$	—
			Three Months Ended March 31, 2014
			Senior			Re-REMIC			Total
			Securities			Securities
	Beginning balance, January 1, 2014		$	7,066		$	334,233		$	341,299
	Total net gains (losses)
	Included in earnings			1,684			3,083			4,767
	Included in other comprehensive income			-1,654			-1,191			-2,845
	Purchases			—			—			—
	Sales			-7,107			-8,626			-15,733
	Payments, net			-215			-4,577			-4,792
	Accretion of discount			226			6,924			7,150
	Ending balance, March 31, 2014		$	—		$	329,846		$	329,846
	The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date		$	—		$	—		$	—
Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis, Gain (Loss) Included in Other Comprehensive Income (Loss) [Table Text Block]	Gains and losses included in earnings for the three months ended March 31, 2015 and 2014 are reported in the following statement of comprehensive income line descriptions:
			Other Loss, Investment Loss, net
			Three Months Ended March 31,
			2015			2014
	Total gains (losses) included in earnings for the period		$	3,432		$	4,767
	Change in unrealized gains (losses) relating to Level 3 assets still held at reporting date		$	—		$	—
Mortgage Backed Securities Fair Value [Table Text Block]	MBS, at fair value(1)(2), consisted of the following as of the dates indicated:
			March 31, 2015												December 31, 2014
			Fair			Net			Percent of			Weighted		Weighted	Fair		Net		Percent of			Weighted		Weighted
			Value			Unamortized			Total			Average		Average	Value		Unamortized		Total			Average		Average
						Premium			Fair			Life		Rating (3)			Premium		Fair			Life		Rating (3)
						(Discount)			Value								(Discount)		Value
	Trading:
	Fannie Mae		$	2,214,210		$	—			56.36	%		7.5	AAA	$	2,064,465	$	—		56.07	%		8.1	AAA
	Freddie Mac			1,473,526			—			37.51	%		7.5	AAA		1,349,835		—		36.66	%		8.2	AAA
	Available-for-sale:
	Fannie Mae			28			—			—			4.6	AAA		40		—		—			4.9	AAA
	Private-label			241,017			-116,839			6.13	%		10.2	NR		267,437		-133,333		7.27	%		10.4	NR
			$	3,928,781		$	-116,839			100	%				$	3,681,777	$	-133,333		100	%
		-1	The Company’s MBS portfolio was primarily comprised of fixed-rate MBS at March 31, 2015 and December 31, 2014. The weighted-average interest rate of the MBS portfolio at March 31, 2015 and December 31, 2014 was 3.92% and 3.93%, respectively.
		-2	As of March 31, 2015 and December 31, 2014, the Company’s MBS investments with a fair value of $3,602,372 and $3,376,025, respectively, were pledged as collateral for repurchase agreements.
		-3	The securities issued by Fannie Mae and Freddie Mac are not rated by any rating agency; however, they are commonly thought of as having an implied rating of “AAA.” There is no assurance, particularly given the downgrade of the U.S. credit rating to “AA+” by Standard & Poor’s during the quarter ended September 30, 2011 and Fitch Ratings Inc.’s announcement on October 15, 2013 that it had placed the U.S. credit rating on negative watch, that these securities would receive such a rating if they were ever rated by a rating agency. The weighted-average rating of the Company’s private-label senior securities is calculated based on face value of the securities.
Private Label MBS Available-for-sale Accretable Yield [Table Text Block]	The following table presents the changes in the accretable yield on available-for-sale, private-label MBS for the three months ended March 31, 2015 and 2014:
			Three Months Ended March 31,
			2015			2014
	Beginning balance		$	202,108		$	326,330
	Accretion of discount			-5,043			-7,150
	Reclassifications, net			-9,182			4,645
	Sales			-12,585			-12,892
	Ending balance		$	175,298		$	310,933
Unrealized Gain (Loss) on Investments [Table Text Block]	The Company’s available-for-sale MBS are carried at fair value in accordance with ASC 320, Debt and Equity Securities (“ASC 320”), with resulting unrealized gains and losses reflected as other comprehensive income or loss. Gross unrealized gains and losses on these securities were the following as of the dates indicated:
			March 31, 2015
			Amortized			Unrealized
			Cost/Cost
			Basis (1)
						Gains			Losses			Fair Value
	Agency-backed MBS		$	25		$	3		$	—		$	28
	Private-label MBS			204,389			36,633			-5			241,017
	Total		$	204,414		$	36,636		$	-5		$	241,045
		-1	The amortized cost of MBS includes unamortized net discounts of $116,839 at March 31, 2015.
			December 31, 2014
			Amortized			Unrealized
			Cost/Cost
			Basis (1)
						Gains			Losses			Fair Value
	Agency-backed MBS		$	36		$	4		$	—		$	40
	Private-label MBS			219,904			47,533			—			267,437
	Total		$	219,940		$	47,537		$	—		$	267,477
		-1	The amortized cost of MBS includes unamortized net discounts of $133,333 at December 31, 2014.
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block]	The following table presents a summary of cumulative other-than-temporary impairment charges recognized on the available-for-sale MBS held as of the dates indicated:
			Three Months Ended March 31,
			2015			2014
	Cumulative other-than-temporary impairment, beginning balance		$	18,903		$	23,663
	Decreases related to other-than-temporary impairments on sold securities			—			-2,636
	Cumulative other-than-temporary impairment, ending balance		$	18,903		$	21,027
Realized Gain (Loss) on Investments [Table Text Block]	The following table presents the results of sales of MBS for the periods indicated:
			Three Months Ended March 31,
			2015						2014
			Agency-Backed			Private-Label			Agency-Backed			Private-Label
			MBS			MBS			MBS			MBS
	Proceeds from sales		$	130,666		$	20,859		$	—		$	15,733
	Gross gains			399			3,348			—			4,669
	Gross losses			8			—			—			—
Investment [Table Text Block]	The Company’s other investments consisted of the following as of the dates indicated:
			March 31, 2015			December 31, 2014
	Interest-only MBS		$	207		$	212
	Non-public equity securities			975			975
	Investment funds			637			650
	Total other investments		$	1,819		$	1,837

Borrowings_Tables

Borrowings (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule of Repurchase Agreements [Table Text Block]	The following table provides information regarding the Company’s outstanding repurchase agreement borrowings as of March 31, 2015 and December 31, 2014:
			March 31, 2015			December 31, 2014
	Pledged with agency-backed MBS:
	Repurchase agreements outstanding		$	3,308,802		$	3,137,586
	Agency-backed MBS collateral, at fair value			3,495,969			3,300,383
	Net amount (1)			187,167			162,797
	Weighted-average rate			0.36	%		0.38	%
	Weighted-average term to maturity			14.0 days			14.0 days
	Pledged with private-label MBS:
	Repurchase agreements outstanding		$	62,888		$	42,189
	Private-label MBS collateral, at fair value			106,403			75,642
	Net amount (1)			43,515			33,453
	Weighted-average rate			2.03	%		1.98	%
	Weighted-average term to maturity			21.4 days			21.8 days
	Total MBS:
	Repurchase agreements outstanding		$	3,371,690		$	3,179,775
	MBS collateral, at fair value			3,602,372			3,376,025
	Net amount (1)			230,682			196,250
	Weighted-average rate			0.39	%		0.4	%
	Weighted-average term to maturity			14.1 days			14.1 days
		-1	Net amount represents the value of collateral in excess of corresponding repurchase obligation. The amount of collateral at-risk is limited to the outstanding repurchase obligation and not the entire collateral balance.
	The following table provides information regarding the Company’s outstanding repurchase agreement borrowings during the three months ended March 31, 2015 and 2014:
			March 31, 2015			March 31, 2014
	Weighted-average outstanding balance during the three months ended		$	3,219,172		$	1,680,941
	Weighted-average rate during the three months ended			0.38	%		0.41	%
Schedule of Long-term Debt Instruments [Table Text Block]	The Company’s long-term debentures consisted of the following as of the dates indicated:
			March 31, 2015								December 31, 2014
			Senior			Senior			Trust		Senior		Trust
			Notes Due 2025			Notes Due 2023			Preferred Debt		Notes Due 2023		Preferred Debt
	Outstanding Principal			$35,300		$	25,000		$	15,000	$	25,000	$	15,000
	Annual Interest Rate			6.75%			6.63%			LIBOR +		6.63%		LIBOR +
										2.25 – 3.00%				2.25 – 3.00%
	Interest Payment Frequency			Quarterly			Quarterly			Quarterly		Quarterly		Quarterly
	Weighted-Average Interest Rate			6.75%			6.63%			3.00%		6.63%		2.98%
	Maturity			15-Mar-25			1-May-23			2033 – 2035		1-May-23		2033 – 2035
	Early Redemption Date			15-Mar-18			1-May-16			2008 – 2010		1-May-16		2008 – 2010

Derivative_Financial_Instrumen1

Derivative Financial Instruments and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments [Table Text Block]	The Company held the following derivative instruments as of the dates indicated:
			March 31, 2015				December 31, 2014
			Notional		Fair Value		Notional		Fair Value
			Amount				Amount
	Eurodollar futures:
	Derivative assets		$	—	$	—	$	2,445,000	$	751
	Derivative liabilities			42,725,000		-112,816		38,645,000		-76,848
	Total Eurodollar futures(1)			42,725,000		-112,816		41,090,000		-76,097
	10-year swap futures:
	Derivative assets			—		—		—		—
	Derivative liabilities			845,000		-62,079		1,145,000		-47,460
	Total 10-year swap futures(2)			845,000		-62,079		1,145,000		-47,460
	10-year U.S. Treasury note futures(3)			50,000		-211		—		—
	Commitment to purchase MBS(4)			217,544		1,508		200,000		516
	Commitment to sell MBS(5)			100,000		-687		—		—
		-1	The $42,725,000 total notional amount of Eurodollar futures contracts as of March 31, 2015 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2015 and 2019. The maximum notional outstanding for any future quarterly period did not exceed $2,525,000 as of March 31, 2015 and $2,325,000 as of December 31, 2014. As of March 31, 2015, the Company maintained $136,051 as a deposit and margin against the open Eurodollar futures contracts.
		-2	The $845,000 represents the total notional amount of 10-year swap futures as of March 31, 2015, of which $480,000 of notional amount matures in June 2015 and $365,000 in notional amount matures in March 2024. As of March 31, 2015, the Company maintained $76,100 as a deposit and margin against the open 10-year swap futures contracts.
		-3	The $50,000 total notional amount of 10-year Treasury note futures as of March 31, 2015 represents the accumulation of 10-year Treasury note futures that mature in June 2015. As of March 31, 2015, the Company maintained $886 as a deposit and margin against the open 10-year Treasury note futures.
		-4	The total notional amount of commitment to purchase MBS represents forward commitments to purchase fixed-rate MBS securities.
		-5	The total notional amount of commitment to sell MBS represents forward commitments to sell fixed-rate MBS securities.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following tables present the computations of basic and diluted earnings per share for the periods indicated:
		Three Months Ended March 31,
		2015				2014
	(Shares in thousands)	Basic		Diluted		Basic		Diluted
	Weighted-average shares outstanding
	Common stock		22,973		22,973		16,808		16,808
	Performance share units and unvested restricted stock		—		—		—		273
	Weighted-average common and common equivalent shares outstanding		22,973		22,973		16,808		17,081
	Net (loss) income applicable to common stock	$	-42,185	$	-42,185	$	7,033	$	7,033
	Net (loss) income per common share	$	-1.84	$	-1.84	$	0.42	$	0.41

Equity_Tables

Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Schedule of Dividends Payable [Table Text Block]	The Board of Directors has approved and the Company has declared the following dividends to date in 2015:
	Quarter Ended	Dividend		Declaration Date		Record Date		Pay Date
		Amount
	31-Mar	$	0.875	10-Mar		31-Mar		30-Apr
	The Board of Directors approved and the Company declared and paid the following dividends for 2014:
	Quarter Ended	Dividend		Declaration Date			Record Date		Pay Date
		Amount
	31-Dec	$	0.875		18-Dec			31-Dec		30-Jan-15
	30-Sep		0.875		17-Sep			29-Sep		31-Oct
	30-Jun		0.875		11-Jun			30-Jun		31-Jul
	31-Mar		0.875		13-Mar			31-Mar		30-Apr

Revisions_to_Previously_Report1

Revisions to Previously Reported Financial Statements (Tables)	3 Months Ended
	Mar. 31, 2015
Accounting Changes and Error Corrections [Abstract]
Schedule of Error Corrections and Prior Period Adjustments [Table Text Block]	The following table sets forth the affected line items within the Company’s previously reported consolidated financial statements for the three months ended March 31, 2014.
		Three Months Ended March 31, 2014
		As Previously Reported		Revision		As Revised
	Other comprehensive income (loss), net of taxes:
	Unrealized gains for the period on available-for-sale securities	$	2,215	$	-1,241	$	974
	Reclassification:
	Included in investment loss, net, in the statement of comprehensive income related to sales of available-for-sale securities		-4,319		1,241		-3,078
	Total other comprehensive loss	$	-2,104	$	—	$	-2,104
	The following tables set forth the affected line items within the Company’s previously reported consolidated balance sheets as of December 31, 2014 and 2013.
		As of December 31, 2014
		As Previously Reported		Revision		As Revised
	Accumulated other comprehensive income, net of taxes	$	42,793	$	-6,921	$	35,872
	Accumulated deficit	$	-1,298,018	$	6,921	$	-1,291,097
		As of December 31, 2013
		As Previously Reported		Revision		As Revised
	Accumulated other comprehensive income, net of taxes	$	53,190	$	-6,921	$	46,269
	Accumulated deficit	$	-1,228,926	$	6,921	$	-1,222,005

Financial_Instruments_Details

Financial Instruments (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Financial assets, Carrying Amount
Cash and cash equivalents, Carrying Amount	$15,315	$33,832
Interest receivable, Carrying Amount	11,269	10,701
Sold securities receivable, Carrying Amount	78,915	0
Other receivables, Carrying Amount	528	1,138
MBS, Carrying Amount
Agency-backed MBS, Carrying Amount	3,687,764	3,414,340
Private-label MBS, Carrying Amount	241,017	267,437
Derivative assets, Carrying Amount	1,508	1,267
Other Investments, Carrying Amount	1,819	1,837
Deposits, Carrying Amount	213,037	160,427
Financial liabilities, Carrying Amount
Repurchase agreements, Carrying Amount	3,371,690	3,179,775
Interest payable, Carrying Amount	1,162	1,106
Long-term debt, Carrying Amount	75,300	40,000
Derivative liabilities, Carrying Amount	175,793	124,308
Purchased securities payable, Carrying Amount	148,252	0
Accounts payable, accrued expenses and other liabilities, Carrying Amount	751	1,006
Financial assets, Estimated Fair Value
Cash and cash equivalents, Estimated Fair Value	15,315	33,832
Interest receivable, Estimated Fair Value	11,269	10,701
Sold securities receivable, Estimated Fair Value	78,915	0
Other receivables, Estimated Fair Value	528	1,138
MBS, Estimated Fair Value
Agency-backed MBS, Estimated Fair Value	3,687,764	3,414,340
Private-label MBS, Estimated Fair Value	241,017	267,437
Derivative assets, Estimated Fair Value	1,508	1,267
Other investments, Estimated Fair Value	1,819	1,837
Deposits, Estimated Fair Value	213,037	160,427
Financial liabilities, Estimated Fair Value
Repurchase agreements, Estimated Fair Value	3,371,690	3,179,775
Interest payable, Estimated Fair Value	1,162	1,106
Long-term debt, Estimated Fair Value	75,000	39,200
Derivative liabilities, Estimated Fair Value	175,793	124,308
Purchased securities payable, Estimated Fair Value	148,252	0
Accounts payable, accrued expenses and other liabilities, Estimated Fair Value	$751	$1,006

Financial_Instruments_Details_

Financial Instruments (Details 1) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
MBS, at fair value
Trading, Agency-backed MBS	$3,687,736	$3,414,300
Available-for-sale
Agency-backed MBS	28	40
Private-label MBS	241,017	267,437
Total available-for-sale	241,045	267,477
Total MBS	3,928,781	3,681,777
Derivative assets, at fair value	1,508	1,267
Derivative liabilities, at fair value	-175,793	-124,308
Interest-only MBS, at fair value	207	212
Total	3,754,703	3,558,948
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
MBS, at fair value
Trading, Agency-backed MBS	0	0
Available-for-sale
Agency-backed MBS	0	0
Private-label MBS	0	0
Total available-for-sale	0	0
Total MBS	0	0
Derivative assets, at fair value	0	751
Derivative liabilities, at fair value	-175,106	-124,308
Interest-only MBS, at fair value	0	0
Total	-175,106	-123,557
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
MBS, at fair value
Trading, Agency-backed MBS	3,687,736	3,414,300
Available-for-sale
Agency-backed MBS	28	40
Private-label MBS	0	0
Total available-for-sale	28	40
Total MBS	3,687,764	3,414,340
Derivative assets, at fair value	1,508	516
Derivative liabilities, at fair value	-687	0
Interest-only MBS, at fair value	0	0
Total	3,688,585	3,414,856
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
MBS, at fair value
Trading, Agency-backed MBS	0	0
Available-for-sale
Agency-backed MBS	0	0
Private-label MBS	241,017	267,437
Total available-for-sale	241,017	267,437
Total MBS	241,017	267,437
Derivative assets, at fair value	0	0
Derivative liabilities, at fair value	0	0
Interest-only MBS, at fair value	207	212
Total	$241,224	$267,649

Financial_Instruments_Details_1

Financial Instruments (Details 2)	Mar. 31, 2015	Dec. 31, 2014
	Scores	Scores
Underlying Collateral Quantitative Disclosures [Line Items]
Original loan-to-value	67.00%	68.00%
Original FICO score	721	722
Three-month prepayment rate	11.00%	11.00%
Three-month loss severities	42.00%	41.00%
Weighted average coupon	2.80%	2.96%

Financial_Instruments_Details_2

Financial Instruments (Details 3) (Private label MBS [Member])	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	5.47%	5.55%
Default rate	3.05%	3.09%
Loss severity rate	42.13%	42.25%
Prepayment rate	10.99%	11.23%
Maximum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	10.00%	10.00%
Default rate	8.25%	8.80%
Loss severity rate	57.50%	57.50%
Prepayment rate	17.70%	17.70%
Minimum [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount rate	5.15%	5.15%
Default rate	1.00%	1.00%
Loss severity rate	29.21%	29.23%
Prepayment rate	7.40%	7.40%

Financial_Instruments_Details_3

Financial Instruments (Details 4) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$267,437	$341,299
Total net gains (losses)
Included in earnings	3,432	4,767
Included in other comprehensive income	-10,905	-2,845
Purchases	0	0
Sales	-20,859	-15,733
Payments, net	-3,131	-4,792
Accretion of discount	5,043	7,150
Ending balance	241,017	329,846
The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date	0	0
Senior Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	0	7,066
Total net gains (losses)
Included in earnings	0	1,684
Included in other comprehensive income	0	-1,654
Purchases	0	0
Sales	0	-7,107
Payments, net	0	-215
Accretion of discount	0	226
Ending balance	0	0
The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date	0	0
Re-REMIC Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	267,437	334,233
Total net gains (losses)
Included in earnings	3,432	3,083
Included in other comprehensive income	-10,905	-1,191
Purchases	0	0
Sales	-20,859	-8,626
Payments, net	-3,131	-4,577
Accretion of discount	5,043	6,924
Ending balance	241,017	329,846
The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date	$0	$0

Financial_Instruments_Details_4

Financial Instruments (Details 5) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other Loss, Investment Loss, net
Total gains (losses) included in earnings for the period	$3,432	$4,767
The amount of net gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to Level 3 assets still held at the reporting date	$0	$0

Financial_Instruments_Details_5

Financial Instruments (Details 6) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	$3,928,781	[1],[2]	$3,681,777	[1],[2]
Net Unamortized Premium (Discount)	-116,839		-133,333
Percentage of Total Fair Value	100.00%		100.00%
Available-for-sale, Private Label Mortgage Backed Securities [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	241,017	[1],[2]	267,437	[1],[2]
Net Unamortized Premium (Discount)	-116,839		-133,333
Percentage of Total Fair Value	6.13%		7.27%
Weighted Average Life	10 years 2 months 12 days		10 years 4 months 24 days
Weighted Average Rating	NR	[3]	NR	[3]
Trading, Fannie Mae [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	2,214,210	[1],[2]	2,064,465	[1],[2]
Net Unamortized Premium (Discount)	0		0
Percentage of Total Fair Value	56.36%		56.07%
Weighted Average Life	7 years 6 months		8 years 1 month 6 days
Weighted Average Rating	AAA	[3]	AAA	[3]
Trading, Freddie Mac [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	1,473,526	[1],[2]	1,349,835	[1],[2]
Net Unamortized Premium (Discount)	0		0
Percentage of Total Fair Value	37.51%		36.66%
Weighted Average Life	7 years 6 months		8 years 2 months 12 days
Weighted Average Rating	AAA	[3]	AAA	[3]
Available-for-sale, Agency-backed, Fannie Mae [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Fair Value	28	[1],[2]	40	[1],[2]
Net Unamortized Premium (Discount)	$0		$0
Percentage of Total Fair Value	0.00%		0.00%
Weighted Average Life	4 years 7 months 6 days		4 years 10 months 24 days
Weighted Average Rating	AAA	[3]	AAA	[3]
[1]	The Companybs MBS portfolio was primarily comprised of fixed-rate MBS at March 31, 2015 and December 31, 2014. The weighted-average interest rate of the MBS portfolio at March 31, 2015 and December 31, 2014 was 3.92% and 3.93%, respectively.
[2]	As of March 31, 2015 and December 31, 2014, the Companybs MBS investments with a fair value of $3,602,372 and $3,376,025, respectively, were pledged as collateral for repurchase agreements.
[3]	The securities issued by Fannie Mae and Freddie Mac are not rated by any rating agency; however, they are commonly thought of as having an implied rating of bAAA.b There is no assurance, particularly given the downgrade of the U.S. credit rating to bAA+b by Standard & Poorbs during the quarter ended September 30, 2011 and Fitch Ratings Inc.bs announcement on October 15, 2013 that it had placed the U.S. credit rating on negative watch, that these securities would receive such a rating if they were ever rated by a rating agency. The weighted-average rating of the Companybs private-label senior securities is calculated based on face value of the securities.

Financial_Instruments_Details_6

Financial Instruments (Details 7) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$202,108	$326,330
Accretion of discount	-5,043	-7,150
Reclassifications, net	-9,182	4,645
Sales	-12,585	-12,892
Ending balance	$175,298	$310,933

Financial_Instruments_Details_7

Financial Instruments (Details 8) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost/Cost Basis	$204,414	[1]	$219,940	[2]
Unrealized Gains	36,636		47,537
Unrealized Losses	-5		0
Fair Value	241,045		267,477
Agency Backed MBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost/Cost Basis	25	[1]	36	[2]
Unrealized Gains	3		4
Unrealized Losses	0		0
Fair Value	28		40
Private Label Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost/Cost Basis	204,389	[1]	219,904	[2]
Unrealized Gains	36,633		47,533
Unrealized Losses	-5		0
Fair Value	$241,017		$267,437
[1]	The amortized cost of MBS includes unamortized net discounts of $116,839 at March 31, 2015.
[2]	The amortized cost of MBS includes unamortized net discounts of $133,333 at December 31, 2014.

Financial_Instruments_Details_8

Financial Instruments (Details 9) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cumulative other-than-temporary impairment, beginning balance	$18,903	$23,663
Decreases related to other-than-temporary impairments on sold securities	0	-2,636
Cumulative other-than-temporary impairment, ending balance	$18,903	$21,027

Financial_Instruments_Details_9

Financial Instruments (Details 10) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Agency Backed MBS [Member]
Proceeds from Sales of Mortgage Backed Securities [Line Items]
Proceeds from sales	$130,666	$0
Gross gains	399	0
Gross losses	8	0
Private label MBS [Member]
Proceeds from Sales of Mortgage Backed Securities [Line Items]
Proceeds from sales	20,859	15,733
Gross gains	3,348	4,669
Gross losses	$0	$0

Recovered_Sheet1

Financial Instruments (Details 11) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Interest-only MBS	$207	$212
Non-public equity securities	975	975
Investment funds	637	650
Total other investments	$1,819	$1,837

Recovered_Sheet2

Financial Instruments (Details Textual) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value Inputs Assets Quantitative Information [Line Items]
Company's Interest in Non Public Equity Securities and Investment Funds	$1,612	$1,625
Weighted Average Coupon Rate for MBS Portfolio	3.92%	3.93%
Pledged Assets Separately Reported, Securities Pledged as Collateral, at Fair Value	3,602,372	3,376,025
Financial Instrument Unamortized Discount Premium Net	$116,839	$133,333

Borrowings_Details

Borrowings (Details) (USD $)	3 Months Ended			12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Repurchase Agreement Counterparty [Line Items]
Repurchase agreements outstanding	$3,371,690			$3,179,775
MBS collateral, at fair value	3,602,372			3,376,025
Net amount	230,682	[1]		196,250	[1]
Weighted-average rate	0.39%			0.40%
Weighted-average term to maturity (in days)	14.1 days			14.1 days
Weighted-average outstanding balance	3,219,172		1,680,941
Weighted-average rate	0.38%		0.41%
Pledged with agency-backed MBS [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase agreements outstanding	3,308,802			3,137,586
MBS collateral, at fair value	3,495,969			3,300,383
Net amount	187,167	[1]		162,797	[1]
Weighted-average rate	0.36%			0.38%
Weighted-average term to maturity (in days)	14.0 days			14.0 days
Pledged with private-label MBS [Member]
Repurchase Agreement Counterparty [Line Items]
Repurchase agreements outstanding	62,888			42,189
MBS collateral, at fair value	106,403			75,642
Net amount	$43,515	[1]		$33,453	[1]
Weighted-average rate	2.03%			1.98%
Weighted-average term to maturity (in days)	21.4 days			21.8 days
[1]	Net amount represents the value of collateral in excess of corresponding repurchase obligation. The amount of collateral at-risk is limited to the outstanding repurchase obligation and not the entire collateral balance.

Borrowings_Details_1

Borrowings (Details 1) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Trust Preferred Debt [Member]
Debt Instrument [Line Items]
Outstanding Principal	$15,000	$15,000
Annual Interest Rate	LIBOR + 2.25 – 3.00%	LIBOR + 2.25 – 3.00%
Interest Payment Frequency	Quarterly	Quarterly
Weighted-Average Interest Rate	3.00%	2.98%
Maturity	2033 – 2035	2033 – 2035
Early Redemption Date	2008 – 2010	2008 – 2010
Senior Notes Due 2025 [Member]
Debt Instrument [Line Items]
Outstanding Principal	35,300
Annual Interest Rate	6.75%
Interest Payment Frequency	Quarterly
Weighted-Average Interest Rate	6.75%
Maturity	15-Mar-25
Early Redemption Date	15-Mar-18
Senior Notes Due 2023 [Member]
Debt Instrument [Line Items]
Outstanding Principal	$25,000	$25,000
Annual Interest Rate	6.63%	6.63%
Interest Payment Frequency	Quarterly	Quarterly
Weighted-Average Interest Rate	6.63%	6.63%
Maturity	1-May-23	1-May-23
Early Redemption Date	1-May-16	1-May-16

Borrowings_Details_Textual

Borrowings (Details Textual) (USD $)	3 Months Ended		1 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 18, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term Debt	$75,300			$40,000
Proceeds from Issuance of Long-term Debt	34,188	0
Senior Notes Due In 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt			35,300
Proceeds from Issuance of Long-term Debt			$34,063
Debt Instrument, Frequency of Periodic Payment	payable quarterly in arrears on March 15, June 15, September 15 and December 15 of each year, beginning on June 15, 2015.
Debt Instrument, Interest Rate, Stated Percentage			6.75%
Debt Instrument, Maturity Date			15-Mar-25

Derivative_Financial_Instrumen2

Derivative Financial Instruments and Hedging Activities (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Derivative [Line Items]
Derivative assets, Fair Value	$1,508		$1,267
Derivative liabilities, Fair Value	-175,793		-124,308
No Hedge Designation [Member] | Eurodollar Futures Asset [Member]
Derivative [Line Items]
Derivative asset, Notional Amount	0		2,445,000
Derivative assets, Fair Value	0		751
No Hedge Designation [Member] | Eurodollar Futures Liabilities [Member]
Derivative [Line Items]
Derivative liabilities, Notional Amount	42,725,000		38,645,000
Derivative liabilities, Fair Value	-112,816		-76,848
No Hedge Designation [Member] | Eurodollar Futures [Member]
Derivative [Line Items]
Notional Amount	42,725,000	[1]	41,090,000	[1]
Fair Value	-112,816	[1]	-76,097	[1]
No Hedge Designation [Member] | 10-Year Swap Futures Asset [Member]
Derivative [Line Items]
Derivative asset, Notional Amount	0		0
Derivative assets, Fair Value	0		0
No Hedge Designation [Member] | 10-Year Swap Futures Liablities [Member]
Derivative [Line Items]
Derivative liabilities, Notional Amount	845,000		1,145,000
Derivative liabilities, Fair Value	-62,079		-47,460
No Hedge Designation [Member] | 10-Year Swap Futures [Member]
Derivative [Line Items]
Notional Amount	845,000	[2]	1,145,000	[2]
Fair Value	-62,079	[2]	-47,460	[2]
No Hedge Designation [Member] | Commitment to Purchase MBS [Member]
Derivative [Line Items]
Notional Amount	217,544	[3]	200,000	[3]
Fair Value	1,508	[3]	516	[3]
No Hedge Designation [Member] | Commitment to Sell MBS [Member]
Derivative [Line Items]
Notional Amount	100,000	[4]	0	[4]
Fair Value	-687	[4]	0	[4]
No Hedge Designation [Member] | 10-year U.S. Treasury note futures [Member]
Derivative [Line Items]
Notional Amount	50,000	[5]	0	[5]
Fair Value	($211)	[5]	$0	[5]
[1]	The $42,725,000 total notional amount of Eurodollar futures contracts as of March 31, 2015 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2015 and 2019. The maximum notional outstanding for any future quarterly period did not exceed $2,525,000 as of March 31, 2015 and $2,325,000 as of December 31, 2014. As of March 31, 2015, the Company maintained $136,051 as a deposit and margin against the open Eurodollar futures contracts.
[2]	The $845,000 represents the total notional amount of 10-year swap futures as of March 31, 2015, of which $480,000 of notional amount matures in June 2015 and $365,000 in notional amount matures in March 2024. As of March 31, 2015, the Company maintained $76,100 as a deposit and margin against the open 10-year swap futures contracts.
[3]	The total notional amount of commitment to purchase MBS represents forward commitments to purchase fixed-rate MBS securities.
[4]	The total notional amount of commitment to sell MBS represents forward commitments to sell fixed-rate MBS securities.
[5]	The $50,000 total notional amount of 10-year Treasury note futures as of March 31, 2015 represents the accumulation of 10-year Treasury note futures that mature in June 2015. As of March 31, 2015, the Company maintained $886 as a deposit and margin against the open 10-year Treasury note futures.

Derivative_Financial_Instrumen3

Derivative Financial Instruments and Hedging Activities (Details Textual) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Derivative [Line Items]
Loss on Derivative Instruments, Pretax	$76,119		$23,480
Deposit Assets	213,037			160,427
Eurodollar Futures [Member] | No Hedge Designation [Member]
Derivative [Line Items]
Deposit Assets	136,051
Notional Amount	42,725,000	[1]		41,090,000	[1]
Eurodollar Futures [Member] | No Hedge Designation [Member] | Maximum [Member]
Derivative [Line Items]
Notional Amount	2,525,000			2,325,000
10-Year Swap Futures [Member] | No Hedge Designation [Member]
Derivative [Line Items]
Deposit Assets	76,100
Notional Amount	845,000	[2]		1,145,000	[2]
10-Year Swap Futures [Member] | No Hedge Designation [Member] | Matures In March 2024 [Member]
Derivative [Line Items]
Notional Amount	365,000
10-Year Swap Futures [Member] | No Hedge Designation [Member] | Matures In June 2015 [Member]
Derivative [Line Items]
Notional Amount	480,000
10-year U.S. Treasury note futures [Member] | No Hedge Designation [Member]
Derivative [Line Items]
Deposit Assets	886
Notional Amount	$50,000	[3]		$0	[3]
[1]	The $42,725,000 total notional amount of Eurodollar futures contracts as of March 31, 2015 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2015 and 2019. The maximum notional outstanding for any future quarterly period did not exceed $2,525,000 as of March 31, 2015 and $2,325,000 as of December 31, 2014. As of March 31, 2015, the Company maintained $136,051 as a deposit and margin against the open Eurodollar futures contracts.
[2]	The $845,000 represents the total notional amount of 10-year swap futures as of March 31, 2015, of which $480,000 of notional amount matures in June 2015 and $365,000 in notional amount matures in March 2024. As of March 31, 2015, the Company maintained $76,100 as a deposit and margin against the open 10-year swap futures contracts.
[3]	The $50,000 total notional amount of 10-year Treasury note futures as of March 31, 2015 represents the accumulation of 10-year Treasury note futures that mature in June 2015. As of March 31, 2015, the Company maintained $886 as a deposit and margin against the open 10-year Treasury note futures.

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Line Items]
Deferred Tax Assets, Net	$113,276	$122,365
Capital Loss Carry forward Expiration Date	2019
Other Capital Loss Carry forward Expiration Date	2020
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	25,379
NCL [Member]
Income Tax Disclosure [Line Items]
Deferred Tax Assets, Valuation Allowance	$51,406	$26,027

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Basic
Weighted-average shares outstanding common stock (in shares)	22,973	16,808
Performance share units and unvested restricted stock (in shares)	0	0
Weighted-average common and common equivalent shares outstanding (in shares)	22,973	16,808
Net (loss) income applicable to common stock	($42,185)	$7,033
Net (loss) income per common share (in dollars per share)	($1.84)	$0.42
Diluted
Weighted-average shares outstanding common stock (in shares)	22,973	16,808
Performance share units and unvested restricted stock (in shares)	0	273
Weighted-average common and common equivalent shares outstanding (in shares)	22,973	17,081
Net (loss) income applicable to common stock	($42,185)	$7,033
Net (loss) income per common share (in dollars per share)	($1.84)	$0.41

Earnings_Per_Share_Details_Tex

Earnings Per Share (Details Textual)	3 Months Ended
	Mar. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	123,242

Equity_Details

Equity (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Dividends Payable [Line Items]
Dividend Amount (in dollars per share)	$0.88	$0.88	$0.88	$0.88	$0.88
Declaration Date	10-Mar-15	18-Dec-14	17-Sep-14	11-Jun-14	13-Mar-14
Record Date	31-Mar-15	31-Dec-14	29-Sep-14	30-Jun-14	31-Mar-14
Pay Date	30-Apr-15	30-Jan-15	31-Oct-14	31-Jul-14	30-Apr-14

Revisions_to_Previously_Report2

Revisions to Previously Reported Financial Statements (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Other comprehensive income (loss), net of taxes:
Unrealized gains for the period on available-for-sale securities	($4,493)	$974
Reclassification:
Included in investment loss, net, in the statement of comprehensive income related to sales of available-for-sale securities (net of taxes of $(380) and $(1,379), respectively)	-3,362	-3,078
Total other comprehensive loss		-2,104
Consolidated Statements Of Changes In Equity [Abstract]
Accumulated other comprehensive income, net of taxes	28,017		35,872	46,269
Accumulated deficit	-1,354,852		-1,291,097	-1,222,005
Scenario, Previously Reported [Member]
Other comprehensive income (loss), net of taxes:
Unrealized gains for the period on available-for-sale securities		2,215
Reclassification:
Included in investment loss, net, in the statement of comprehensive income related to sales of available-for-sale securities (net of taxes of $(380) and $(1,379), respectively)		-4,319
Total other comprehensive loss		-2,104
Consolidated Statements Of Changes In Equity [Abstract]
Accumulated other comprehensive income, net of taxes			42,793	53,190
Accumulated deficit			-1,298,018	-1,228,926
Scenario, Adjustment [Member]
Other comprehensive income (loss), net of taxes:
Unrealized gains for the period on available-for-sale securities		-1,241
Reclassification:
Included in investment loss, net, in the statement of comprehensive income related to sales of available-for-sale securities (net of taxes of $(380) and $(1,379), respectively)		1,241
Total other comprehensive loss		0
Consolidated Statements Of Changes In Equity [Abstract]
Accumulated other comprehensive income, net of taxes			-6,921	-6,921
Accumulated deficit			$6,921	$6,921