Arlington Asset Investment (AAIC) 10-Q 31 Oct 14 2014 Q3 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	9 Months Ended
	Sep. 30, 2014	Oct. 31, 2014	Oct. 31, 2014
		Common Class A [Member]	Common Class B [Member]
Document Information [Line Items]	'	'	'
Entity Registrant Name	'Arlington Asset Investment Corp.	'	'
Entity Central Index Key	'0001209028	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Filer Category	'Accelerated Filer	'	'
Trading Symbol	'AI	'	'
Entity Common Stock, Shares Outstanding	'	22,517,563	449,228
Document Type	'10-Q	'	'
Amendment Flag	'false	'	'
Document Period End Date	30-Sep-14	'	'
Document Fiscal Period Focus	'Q3	'	'
Document Fiscal Year Focus	'2014	'	'

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and cash equivalents	$31,093	$48,628
Receivables	'	'
Interest	9,259	5,173
Other	222	212
Mortgage-backed securities, at fair value	'	'
Available-for-sale	292,849	341,346
Trading	3,176,135	1,576,452
Other investments	1,891	2,065
Derivative assets, at fair value	8,966	8,424
Deferred tax assets, net	147,686	165,851
Deposits	95,216	45,504
Prepaid expenses and other assets	1,379	1,311
Total assets	3,764,696	2,194,966
Liabilities:	'	'
Repurchase agreements	2,668,566	1,547,630
Interest payable	901	774
Accrued compensation and benefits	4,367	5,584
Dividend payable	20,199	14,630
Derivative liabilities, at fair value	67,410	33,129
Purchased securities payable	263,425	0
Accounts payable, accrued expenses and other liabilities	851	1,391
Long-term debt	40,000	40,000
Total liabilities	3,065,719	1,643,138
Commitments and contingencies	0	0
Equity:	'	'
Preferred stock, $0.01 par value, 25,000,000 shares authorized, none issued and outstanding	0	0
Additional paid-in capital	1,896,195	1,727,398
Accumulated other comprehensive income, net of taxes of $7,287 and $9,436, respectively	47,611	53,190
Accumulated deficit	-1,245,058	-1,228,926
Total equity	698,977	551,828
Total liabilities and equity	3,764,696	2,194,966
Common Class A [Member]	'	'
Equity:	'	'
Common stock	225	160
Common Class B [Member]	'	'
Equity:	'	'
Common stock	$4	$6

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
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)	$7,287	$9,436
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)	22,517,563	16,047,965
Common stock, shares outstanding (in shares)	22,517,563	16,047,965
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)	449,228	554,055
Common stock, shares outstanding (in shares)	449,228	554,055

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest income	$33,301	$22,995	$87,231	$64,468
Interest expense	'	'	'	'
Interest on short-term debt	2,422	1,758	6,280	5,061
Interest on long-term debt	554	556	1,657	1,077
Total interest expense	2,976	2,314	7,937	6,138
Net interest income	30,325	20,681	79,294	58,330
Other loss, net	'	'	'	'
Investment loss, net	-6,978	-11,100	-4,979	-35,882
Other loss	-4	-3	-11	-11
Total other loss, net	-6,982	-11,103	-4,990	-35,893
Operating income before other expenses	23,343	9,578	74,304	22,437
Other expenses	'	'	'	'
Compensation and benefits	3,995	3,042	10,141	8,034
Professional services	290	297	1,201	1,973
Business development	45	45	132	107
Occupancy and equipment	107	96	326	328
Communications	47	49	146	142
Other operating expenses	570	501	1,643	1,142
Total other expenses	5,054	4,030	13,589	11,726
Income before income taxes	18,289	5,548	60,715	10,711
Income tax provision	5,442	2,455	21,996	1,247
Net income	12,847	3,093	38,719	9,464
Basic earnings per share (in dollars per share)	$0.62	$0.19	$2.03	$0.60
Diluted earnings per share (in dollars per share)	$0.61	$0.18	$1.99	$0.59
Weighted-average shares outstanding (in thousands)	'	'	'	'
Basic (in shares)	20,577	16,669	19,056	15,761
Diluted (in shares)	21,055	16,845	19,413	15,934
Other comprehensive income, net of taxes	'	'	'	'
Unrealized gains (losses) for the period on available-for-sale securities (net of taxes of $139, $1,471, $1,641, and $9,863, respectively)	219	2,116	2,578	14,192
Reclassification	'	'	'	'
Included in investment gains (loss), net, in the statement of comprehensive income related to sales of available-for-sale securities (net of taxes of $(794), $(1,654), $(3,844), and $(3,161), respectively)	-2,499	-2,380	-8,242	-4,548
Included in investment gain (loss), net, in the statement of comprehensive income related to other-than-temporary impairment charges on available-for-sale securities (net of taxes of $28, $156, $54, and $521, respectively)	43	224	85	749
Comprehensive income	$10,610	$3,053	$33,140	$19,857

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Unrealized gains (losses) for the period on available-for-sale securities, taxes	$139	$1,471	$1,641	$9,863
Included in investment gains (loss), net, in the statement of comprehensive income related to sales of available-for-sale securities, taxes	-794	-1,654	-3,844	-3,161
Included in investment gain (loss), net, in the statement of comprehensive income related to other-than-temporary impairment charges on available-for-sale securities, taxes	$28	$156	$54	$521

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]
Beginning Balances at Dec. 31, 2012	$457,293	$126	$6	$1,638,061	$39,006	($1,219,906)
Beginning Balances (in shares) at Dec. 31, 2012	'	12,560,970	554,055	'	'	'
Net income	49,461	0	0	0	0	49,461
Issuance of Class A common stock	86,964	34	0	86,930	0	0
Issuance of Class A common stock (in shares)	'	3,492,667	0	'	'	'
Forfeitures of Class A common stock	-142	0	0	-142	0	0
Forfeitures of Class A common stock (in shares)	'	-5,672	0	'	'	'
Amortization of Class A common shares issued as stock-based awards	2,549	0	0	2,549	0	0
Other comprehensive income	'	'	'	'	'	'
Net change in unrealized gain on available-for-sale investment securities, (net of taxes)	14,184	0	0	0	14,184	0
Dividends declared	-58,481	0	0	0	0	-58,481
Ending Balances at Dec. 31, 2013	551,828	160	6	1,727,398	53,190	-1,228,926
Ending Balances (in shares) at Dec. 31, 2013	'	16,047,965	554,055	'	'	'
Net income	38,719	0	0	0	0	38,719
Conversion of Class B shares to Class A shares	0	2	-2	0	0	0
Conversion of Class B shares to Class A shares (in shares)	'	104,827	-104,827	'	'	'
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	-1,479	-1	0	-1,478	0	0
Forfeitures of Class A common stock (in shares)	'	-54,476	0	'	'	'
Amortization of Class A common shares issued as stock-based awards	2,981	0	0	2,981	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)	-5,579	0	0	0	-5,579	0
Dividends declared	-54,851	0	0	0	0	-54,851
Ending Balances at Sep. 30, 2014	$698,977	$225	$4	$1,896,195	$47,611	($1,245,058)
Ending Balances (in shares) at Sep. 30, 2014	'	22,517,563	449,228	'	'	'

CONSOLIDATED_STATEMENTS_OF_CHA1

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) (USD $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Net change in unrealized gain on available-for-sale investment securities, taxes	($2,149)	$9,029

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:	'	'
Net income	$38,719	$9,464
Adjustments to reconcile net income to net cash provided by operating activities	'	'
Net investment loss	4,979	35,882
Net discount accretion on mortgage-backed securities	-10,256	-6,332
Deferred tax provision	20,314	3,803
Other	1,502	1,581
Changes in operating assets	'	'
Interest receivable	-4,086	-402
Other receivables	-10	183
Prepaid expenses and other assets	-1,718	-1,156
Changes in operating liabilities	'	'
Accounts payable and other liabilities	-710	-3,955
Accrued compensation and benefits	-1,217	2,483
Net cash provided by operating activities	47,517	41,551
Cash flows from investing activities:	'	'
Purchases of available-for-sale mortgage-backed securities	0	-167,682
Purchases of trading mortgage-backed securities	-1,500,675	-1,139,008
Proceeds from sales of available-for-sale mortgage-backed securities	62,276	54,884
Proceeds from sales of trading mortgage-backed securities	65,251	837,013
Receipt of principal payments on available-for-sale mortgage-backed securities	1,831	4,124
Receipt of principal payments on trading mortgage-backed securities	143,612	132,478
Proceeds from sold securities receivable	0	26,773
(Payments for) proceeds from derivatives and deposits, net	-76,831	31,527
Other	176	15
Net cash used in investing activities	-1,304,360	-219,876
Cash flows from financing activities:	'	'
Proceeds from repurchase agreements, net	1,120,936	77,053
Proceeds from stock issuance, net	167,183	86,964
Proceeds from long-term debt issuance, net	0	24,038
Dividends paid	-49,286	-29,220
Excess tax benefits associated with stock-based awards	475	0
Net cash provided by financing activities	1,239,308	158,835
Net decrease in cash and cash equivalents	-17,535	-19,490
Cash and cash equivalents, beginning of period	48,628	35,837
Cash and cash equivalents, end of period	31,093	16,347
Supplemental cash flow information	'	'
Cash payments for interest	7,732	5,888
Cash payments for taxes	$1,759	$452

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of Presentation	'
	1. Basis of Presentation:
	The consolidated financial statements of Arlington Asset Investment Corp. (Arlington Asset) and its 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 and nine months ended September 30, 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, 2013.
	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	9 Months Ended
	Sep. 30, 2014
Fair Value Disclosures [Abstract]	'
Financial Instruments	'
	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 (MBS), 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 after considering quoted market prices provided by a broker or dealer, or alternative pricing sources with reasonable levels of price transparency. The Company reviews broker or pricing service quotes to determine whether the quotes are relevant, for example, whether an active market exists to provide price transparency or whether the quote is an indicative price or a binding offer. The independent brokers and dealers providing market prices are those who make markets in or specialists with expertise in the valuation of these financial instruments.
	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. The Company utilizes present value techniques based on estimated cash flows of the instrument taking into consideration various assumptions derived by management and other assumptions used by other 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, or the mark, from third-party dealers and the 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:
			30-Sep-14						31-Dec-13
			Carrying Amount			Estimated			Carrying Amount			Estimated
						Fair Value						Fair Value
	Financial assets
	Cash and cash equivalents		$	31,093		$	31,093		$	48,628		$	48,628
	Interest receivable			9,259			9,259			5,173			5,173
	Other receivables			222			222			212			212
	MBS
	Agency-backed MBS			3,176,175			3,176,175			1,576,499			1,576,499
	Private-label MBS
	Senior securities			—			—			7,066			7,066
	Re-REMIC securities			292,809			292,809			334,233			334,233
	Derivative assets			8,966			8,966			8,424			8,424
	Other investments			1,891			1,891			2,065			2,065
	Deposits			95,216			95,216			45,504			45,504
	Financial liabilities
	Repurchase agreements			2,668,566			2,668,566			1,547,630			1,547,630
	Interest payable			901			901			774			774
	Long-term debt			40,000			39,380			40,000			36,620
	Derivative liabilities			67,410			67,410			33,129			33,129
	Purchased securities payable			263,425			263,425			—			—
	Accounts payable, accrued expenses and other liabilities			851			851			1,391			1,391
	Fair Value Hierarchy
	The following tables set forth financial instruments accounted for under ASC 820 by level within the fair value hierarchy as of September 30, 2014 and December 31, 2013. 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
			30-Sep-14
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading
	Agency-backed MBS		$	3,176,135		$	—		$	3,176,135		$	—
	Available-for-sale
	Agency-backed MBS			40			—			40			—
	Private-label MBS
	Senior securities			—			—			—			—
	Re-REMIC securities			292,809			—			—			292,809
	Total available-for-sale			292,849			—			40			292,809
	Total MBS			3,468,984			—			3,176,175			292,809
	Derivative assets, at fair value			8,966			6,862			2,104			—
	Derivative liabilities, at fair value			(67,410	)		(67,347	)		(63	)		—
	Interest-only MBS, at fair value			220			—			—			220
	Total		$	3,410,760		$	(60,485	)	$	3,178,216		$	293,029
			31-Dec-13
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading
	Agency-backed MBS		$	1,576,452		$	—		$	1,576,452		$	—
Available-for-sale
Agency-backed MBS			47			—			47			—
Private-label MBS
Senior securities			7,066			—			—			7,066
Re-REMIC securities			334,233			—			—			334,233
Total available-for-sale			341,346			—			47			341,299
Total MBS			1,917,798			—			1,576,499			341,299
Derivative assets, at fair value			8,424			8,088			336			—
Derivative liabilities, at fair value			(33,129	)		(32,156	)		(973	)		—
Interest-only MBS, at fair value			298			—			—			298
Total		$	1,893,391		$	(24,068	)	$	1,575,862		$	341,597
The total financial assets measured and reported at fair value on a recurring basis and classified within Level 3 were $293,029, or 7.78%, and $341,597, or 15.56%, of the Company’s total assets as of September 30, 2014 and December 31, 2013, respectively.
There were no transfers of securities in or out of Levels 1, 2 or 3 during the three and nine months ended September 30, 2014 or the year ended December 31, 2013.
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 $292,809 and $341,299 as of September 30, 2014 and December 31, 2013, respectively. The private-label MBS are primarily senior and re-REMIC tranches in securitization trusts issued between 2005 and 2010. The senior securities 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. Senior, 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:
		30-Sep-14			31-Dec-13
Original loan-to-value			68	%		69	%
Original FICO score			723			725
Three-month prepayment rate			12	%		14	%
Three-month loss severities			42	%		37	%
Weighted average coupon			2.98	%		3.34	%
The significant unobservable inputs for the valuation model include the following weighted-averages, based on face value, as of the dates indicated:
		30-Sep-14						31-Dec-13
		Senior			Re-REMIC			Senior			Re-REMIC
		Securities(1)			Securities			Securities			Securities
Discount rate			—	%		6.49	%		6	%		6.55	%
Default rate			—	%		3.07	%		9.3	%		3.62	%
Loss severity rate			—	%		42.04	%		50	%		44.82	%
Prepayment rate			—	%		11.21	%		16.3	%		11.69	%
	-1	The Company did not own any senior securities on September 30, 2014.
The ranges of the significant unobservable inputs for the valuation model were as follows as of the dates indicated:
		30-Sep-14						31-Dec-13
		Senior			Re-REMIC			Senior			Re-REMIC
		Securities(1)			Securities			Securities			Securities
Discount rate			—	%		6.00 – 10.00	%		6	%		6.00 – 10.00	%
Default rate			—	%		1.00 – 8.80	%		9.3	%		0.95 – 9.60	%
Loss severity rate			—	%		29.24 – 57.50	%		50	%		29.15 – 57.50	%
Prepayment rate			—	%		7.40 – 17.70	%		16.3	%		6.40 – 19.00	%
	-1	The Company did not own any senior securities on September 30, 2014.
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 and nine months ended September 30, 2014 and 2013.
		Three Months Ended September 30, 2014
		Senior			Re-REMIC			Total
		Securities			Securities
Beginning balance, July 1, 2014		$	—		$	314,148		$	314,148
Total net gains (losses)
Included in earnings			—			3,475			3,475
Included in other comprehensive income			—			(2,860	)		(2,860	)
Purchases			—			—			—
Sales			—			(25,044	)		(25,044	)
Payments, net			—			(3,493	)		(3,493	)
Accretion of discount			—			6,583			6,583
Ending balance, September 30, 2014		$	—		$	292,809		$	292,809
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		$	—		$	(71	)	$	(71	)
		Three Months Ended September 30, 2013
		Senior			Re-REMIC			Total
		Securities			Securities
Beginning balance, July 1, 2013		$	7,246		$	321,674		$	328,920
Total net gains (losses)
Included in earnings			—			4,509			4,509
Included in other comprehensive income			(117	)		72			(45	)
Purchases			—			36,479			36,479
Sales			—			(27,086	)		(27,086	)
Payments, net			(313	)		(5,446	)		(5,759	)
Accretion of discount			221			6,879			7,100
Ending balance, September 30, 2013		$	7,037		$	337,081		$	344,118
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		$	—		$	(380	)	$	(380	)
		Nine Months Ended September 30, 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			1,690			11,317			13,007
Included in other comprehensive income			(1,654	)		(6,070	)		(7,724	)
Purchases			—			—			—
Sales			(7,029	)		(55,246	)		(62,275	)
Payments, net			(319	)		(11,782	)		(12,101	)
Accretion of discount			246			20,357			20,603
Ending balance, September 30, 2014		$	—		$	292,809		$	292,809
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		$	—		$	(122	)	$	(122	)
		Nine Months Ended September 30, 2013
		Senior			Re-REMIC			Total
		Securities			Securities
Beginning balance, January 1, 2013		$	7,519		$	191,567		$	199,086
Total net gains (losses)
Included in earnings			—			12,299			12,299
Included in other comprehensive income			(204	)		17,875			17,671
Purchases			—			167,682			167,682
Sales			—			(54,884	)		(54,884	)
Payments, net			(950	)		(16,205	)		(17,155	)
Accretion of discount			672			18,747			19,419
Ending balance, September 30, 2013		$	7,037		$	337,081		$	344,118
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		$	—		$	(1,270	)	$	(1,270	)
Gains and losses included in earnings for the three and nine months ended September 30, 2014 and 2013 are reported in the following statement of comprehensive income line descriptions:
		Other Loss, Investment Loss, net
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
Total gains (losses) included in earnings for the period		$	3,475		$	4,509		$	13,007		$	12,299
Change in unrealized gains (losses) relating to Level 3 assets still held at reporting date		$	(71	)	$	(380	)	$	(122	)	$	(1,270	)
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 September 30, 2014 and December 31, 2013, these financial assets are classified within the other investments category, represent the Company’s interest in non-public equity securities and investment funds and are valued at $1,671 and $1,767, respectively. For the nine months ended September 30, 2013, the Company recorded losses of $138 in the carrying value of these financial assets. For the three months ended September 30, 2013 and for the three and nine months ended September 30, 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:
		30-Sep-14														31-Dec-13
		Fair			Net Unamortized Premium (Discount)			Percent of Total			Weighted Average Life			Weighted Average Rating(3)		Fair		Net Unamortized Premium (Discount)			Percent of Total			Weighted Average Life		Weighted Average Rating(3)
		Value						Fair								Value					Fair
								Value													Value
Trading
Fannie Mae		$	1,883,424		$	—			54.3	%		8.9			AAA	$	997,488	$	—			52.01	%		9.4		AAA
Freddie Mac			1,292,711			—			37.26	%		9.2			AAA		578,964		—			30.19	%		9.6		AAA
Available-for-sale:
Agency-backed
Fannie Mae			40			—			—			5.3			AAA		47		—			—			5.8		AAA
Private-label
Senior securities			—			—			—			—			—		7,066		(4,789	)		0.37	%		4.8		C-
Re-REMIC securities			292,809			(151,494	)		8.44	%		10.7			NR		334,233		(202,450	)		17.43	%		11.4		NR
		$	3,468,984		$	(151,494	)		100	%						$	1,917,798	$	(207,239	)		100	%
	-1	The Company’s MBS portfolio was primarily comprised of fixed-rate MBS at September 30, 2014 and December 31, 2013. The weighted-average interest rate of the MBS portfolio at September 30, 2014 and December 31, 2013 was 3.92% and 3.90%, respectively.
	-2	As of September 30, 2014 and December 31, 2013, the Company’s MBS investments with a fair value of $2,862,397 and $1,673,911, 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. 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 the 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 and nine months ended September 30, 2014 and 2013:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
Beginning balance		$	291,128		$	317,695		$	326,330		$	207,853
Accretion of discount			(6,583	)		(7,099	)		(20,602	)		(19,418	)
Reclassifications, net			1,960			18,639			15,332			51,248
Acquisitions			—			36,901			—			150,646
Sales			(19,087	)		(27,372	)		(53,642	)		(51,565	)
Ending balance		$	267,418		$	338,764		$	267,418		$	338,764
For the available-for-sale, private-label MBS acquired during the three and nine months ended September 30, 2014 and 2013, the contractually required payments receivable, the cash flow expected to be collected, and the fair value at the acquisition date were as follows for the dates indicated:
		Three Months Ended September 30,						Nine Months Ended September 30,
		2014			2013			2014			2013
Contractually required payments receivable		$	—		$	87,640		$	—		$	420,500
Cash flows expected to be collected			—			73,380			—			318,328
Basis in acquired securities			—			36,479			—			167,682
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:
		30-Sep-14
		Amortized			Unrealized
		Cost/Cost
		Basis(1)			Gains			Losses			Fair Value
Agency-backed MBS		$	36		$	4		$	—		$	40
Private-label MBS
Senior securities			—			—			—			—
Re-REMIC securities			237,910			54,915			(16	)		292,809
Total		$	237,946		$	54,919		$	(16	)	$	292,849
	-1	The amortized cost of MBS includes unamortized net discounts of $151,494 at September 30, 2014.
		31-Dec-13
		Amortized			Unrealized
		Cost/Cost
		Basis(1)			Gains			Losses			Fair Value
Agency-backed MBS		$	43		$	4		$	—		$	47
Private-label MBS
Senior securities			5,412			1,654			—			7,066
Re-REMIC securities			273,264			60,970			(1	)		334,233
Total		$	278,719		$	62,628		$	(1	)	$	341,346
	-1	The amortized cost of MBS includes unamortized net discounts of $207,239 at December 31, 2013.
For the three and nine months ended September 30, 2014, the Company recorded other-than-temporary impairment charges of $71 and $122, respectively, as a component of investment loss, net on the consolidated statements of comprehensive income related to deterioration in credit quality on available-for-sale, private- label MBS with a cost basis of $2,139 and $2,174, respectively, prior to recognizing the other-than-temporary impairment charges. For the three and nine months ended September 30, 2013, the Company recorded other-than-temporary impairment charges of $380 and $1,270, respectively, as a component of investment loss, net on the consolidated statements of comprehensive income related to deterioration in credit quality on available-for-sale, private-label MBS with a cost basis of $10,104 and $11,688, respectively, prior to recognizing the other-than-temporary impairment charges.
The following table presents a summary of other-than-temporary impairment charges included in earnings for the periods indicated and cumulative other-than-temporary impairment charges recognized on the MBS held as of the dates indicated:
		Three Months Ended September 30,						Nine Months Ended
								September 30,
		2014			2013			2014			2013
Cumulative other-than-temporary impairment, beginning balance		$	19,687		$	23,283		$	23,663		$	23,768
Additions
Other-than-temporary impairments not previously recognized			—			380			122			380
Increases related to other-than-temporary impairments on securities with previously recognized other-than-temporary impairments			71			—			—			890
Reductions
Decreases related to other-than-temporary impairments on sold securities			—			—			(4,027	)		(1,375	)
Cumulative other-than-temporary impairment, ending balance		$	19,758		$	23,663		$	19,758		$	23,663
The following table presents the results of sales of MBS for the periods indicated:
		Three Months Ended September 30,												Nine Months Ended September 30,
		2014						2013						2014				2013
		Agency-Backed			Private-Label			Agency-Backed			Private-Label			Agency-Backed		Private-Label		Agency-Backed			Private- Label
		MBS			MBS			MBS			MBS			MBS		MBS		MBS			MBS
Proceeds from sales		$	65,251		$	25,044		$	309,518		$	27,085		$	65,251	$	62,275	$	837,257		$	54,884
Gross gains			—			3,467			238			4,778			1,351		12,826		531			13,267
Gross losses			218			—			4,118			—			—		—		26,469			—
Other Investments
The Company’s other investments consisted of the following as of the dates indicated:
		30-Sep-14			31-Dec-13
Interest-only MBS		$	220		$	298
Non-public equity securities			975			975
Investment funds			696			792
Total other investments		$	1,891		$	2,065

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Borrowings	'
	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 September 30, 2014 and December 31, 2013, the Company had no amount at risk with a single repurchase agreement counterparty or lender greater than 10% of equity. The following tables provide information regarding the Company’s outstanding repurchase agreement borrowings as of the dates and for the periods indicated:
			30-Sep-14			31-Dec-13
	Outstanding balance		$	2,668,566		$	1,547,630
	Value of assets pledged as collateral
	Agency-backed MBS			2,748,052			1,556,763
	Private-label MBS			114,345			117,148
	Net amount(1)			193,831			126,281
	Weighted-average rate			0.36	%		0.45	%
	Weighted-average term to maturity			14.0 days			13.2 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.
			30-Sep-14			30-Sep-13
	Weighted-average outstanding balance during the three months ended		$	2,658,695		$	1,581,663
	Weighted-average rate during the three months ended			0.36	%		0.44	%
	Weighted-average outstanding balance during the nine months ended		$	2,213,501		$	1,504,878
	Weighted-average rate during the nine months ended			0.37	%		0.44	%
	Long-Term Debt
	As of September 30, 2014 and December 31, 2013, the Company had $40,000 of outstanding long-term debentures. The Company’s long-term debentures consisted of the following as of the dates indicated:
			30-Sep-14						31-Dec-13
			Senior			Trust			Senior		Trust
			Notes			Preferred Debt			Notes		Preferred Debt
	Outstanding Principal		$	25,000		$	15,000		$	25,000	$	15,000
	Annual Interest Rate			6.63%			LIBOR +			6.63%		LIBOR +
							2.25 – 3.00%					2.25 – 3.00%
	Interest Payment Frequency			Quarterly			Quarterly			Quarterly		Quarterly
	Weighted-Average Interest Rate			6.63%			2.98%			6.63%		2.99%
	Maturity			1-May-23			2033 – 2035			1-May-23		2033 – 2035
	Early Redemption Date			1-May-16			2008 – 2010			1-May-16		2008 – 2010

Derivative_Financial_Instrumen

Derivative Financial Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments and Hedging Activities	'
	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 interest rate swaps, Eurodollar futures, swap futures, and U.S. Treasury futures contracts, 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 and nine months ended September 30, 2014 and 2013, 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 and nine months ended September 30, 2014, the Company recorded net gains (losses) of $7,556 and $(62,509), respectively, on these derivatives. For the three and nine months ended September 30, 2013, the Company recorded net (losses) gains of $(14,457) and $44,577, respectively, on these derivatives. The Company held the following derivative instruments as of the dates indicated:
			30-Sep-14					31-Dec-13
			Notional		Fair Value			Notional		Fair Value
			Amount					Amount
	No hedge designation
	Eurodollar futures
	Derivative assets		$	10,208,000	$	3,111		$	8,758,000	$	4,361
	Derivative liabilities			27,752,000		(44,062	)		6,787,000		(30,638	)
	Total Eurodollar futures(1)			37,960,000		(40,951	)		15,545,000		(26,277	)
	10-year swap futures
	Derivative assets			670,000		3,751			635,500		3,727
	Derivative liabilities			460,000		(23,285	)		31,000		(18	)
	Total 10-year swap futures(2)			1,130,000		(19,534	)		666,500		3,709
	5-year U.S. Treasury note futures			—		—			100,000		(1,500	)
	Commitment to purchase MBS(3)			497,569		2,104			169,511		(973	)
	Commitment to sell MBS(4)			50,000		(63	)		125,000		336
		-1	The $37,960,000 total notional amount of Eurodollar futures contracts as of September 30, 2014 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2014 and 2019. As of September 30, 2014, the Company maintained $57,970 as a deposit and margin against the open Eurodollar futures contracts.
		-2	The $1,130,000 represents the total notional amount of 10-year swap futures as of September 30, 2014, of which $765,000 of notional amount matures in December 2014 and $365,000 in notional amount matures in March 2024. As of September 30, 2014, the Company maintained $37,246 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.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	5. Income Taxes:
	The total income tax provision for the three and nine months ended September 30, 2014 was $5,442 and $21,996, respectively. The total income tax provision for the three and nine months ended September 30, 2013 was $2,455 and $1,247, respectively. The Company generated pre-tax book income of $18,289 and $60,715 for the three and nine months ended September 30, 2014, respectively. The Company generated pre-tax book income of $5,548 and $10,711 for the three and nine months ended September 30, 2013, respectively.
	The Company’s effective tax rate for the nine months ended September 30, 2014 and 2013 was 36.2% and 11.64%, respectively. The effective tax rate during the nine months ended September 30, 2014 was lower than the statutory rate due to the changes in deferred taxes. The effective tax rate during the nine months ended September 30, 2013 was lower than the statutory tax rate due to the realization of previously unrecognized tax benefits, including related accrued interest, that were fully reserved.
	As of September 30, 2014, the Company had a net deferred tax asset of $147,686. The Company continues to provide a valuation allowance against the portion of the capital loss carryforwards for which the Company believes is more likely than not that the benefits will not be realized prior to expiration. The Company will continue to assess the need for a valuation allowance at each reporting date.
	As of September 30, 2014, 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 September 30, 2014, there are no on-going examinations.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	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 stock options, 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 September 30,
		2014				2013
	(Shares in thousands)	Basic		Diluted		Basic		Diluted
	Weighted-average shares outstanding
	Common stock		20,577		20,577		16,669		16,669
	Stock options, performance share units, and unvested restricted stock		—		478		—		176
	Weighted-average common and common equivalent shares outstanding		20,577		21,055		16,669		16,845
	Net income applicable to common stock	$	12,847	$	12,847	$	3,093	$	3,093
	Net income per common share	$	0.62	$	0.61	$	0.19	$	0.18
		Nine Months Ended September 30,
		2014				2013
	(Shares in thousands)	Basic		Diluted		Basic		Diluted
	Weighted-average shares outstanding
	Common stock		19,056		19,056		15,761		15,761
	Stock options, performance share units, and unvested restricted stock		—		357		—		173
	Weighted-average common and common equivalent shares outstanding		19,056		19,413		15,761		15,934
	Net income applicable to common stock	$	38,719	$	38,719	$	9,464	$	9,464
	Net income per common share	$	2.03	$	1.99	$	0.6	$	0.59
	The diluted earnings per share for the three and nine months ended September 30, 2014 did not include the antidilutive effect of 38,646 and 29,543 shares, respectively, of stock options, unvested shares of restricted stock, and performance share units. The diluted earnings per share for the three and nine months ended September 30, 2013 did not include the antidilutive effect of 43,598 and 23,796 shares, respectively, of stock options, unvested shares of restricted stock, and performance share units.

Equity

Equity	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Equity	'
	7. Equity:
	Equity Offering
	During the nine months ended September 30, 2014, the Company completed two public offerings of its Class A Common Stock as follows:
	Closing date of the offering			28-Mar-14		8-Sep-14
	Shares sold to public			2,750,000		2,750,000
	Additional shares sold pursuant to the underwriter			312,500		412,500
	over-allotment option
	Total shares of Class A common stock sold in the offering			3,062,500		3,162,500
	Public offering price per share		$	27.4	$	27.61
	Net proceeds(1)		$	81,669	$	85,214
		-1	Net of underwriting discounts and commissions and expenses.
	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 2014:
	Quarter Ended		Dividend Amount		Declaration Date		Record Date		Pay Date
	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
	The Board of Directors approved and the Company declared and paid the following dividends for 2013:
	Quarter Ended		Dividend Amount		Declaration Date		Record Date		Pay Date
	31-Dec		$	0.875		19-Dec		31-Dec		31-Jan-14
	30-Sep			0.875		18-Sep		30-Sep		31-Oct
	30-Jun			0.875		17-Jun		28-Jun		31-Jul
	31-Mar			0.875		15-Mar		28-Mar		30-Apr
	Long-Term Incentive Plan
	On April 7, 2014, the Board of Directors adopted the Arlington Asset Investment Corp. 2014 Long-Term Incentive Plan (2014 Plan). The 2014 Plan was approved by the Company’s shareholders and became effective on July 15, 2014. Under the 2014 Plan, a maximum number of 2,000,000 shares of Class A common stock of the Company, subject to adjustment as set forth in the 2014 Plan, were authorized for issuance and may be issued to employees, directors, consultants and advisors of the Company and its affiliates. As of September 30, 2014, 1,998,774 shares remained available for issuance under the 2014 Plan.
	The 2014 Plan replaced the Arlington Asset Investment Corp. 2011 Long-Term Incentive Plan (2011 Plan). No additional grants will be made under the 2011 Plan. However, previous grants under the 2011 Plan will remain in effect subject to the terms of the 2011 Plan and the applicable award agreement and shares of Class A common stock may be issued under the 2011 Plan, subject to adjustment as set forth in the 2014 Plan. The shares of Class A common stock to be issued under the 2011 Plan are subject to the achievement of performance measures and vesting. As of September 30, 2014 and December 31, 2013, 308,934 and 443,504 shares, respectively, remained available for issuance under the 2011 Plan.
	Depending on the Company’s stock price at the time restricted stock units vest, the actual tax deduction benefit may be more or less than the carrying amount of the previously recorded deferred tax asset. An increase to the tax benefit (windfall) is generated when the tax deduction exceeds the recorded deferred tax asset. This incremental excess tax benefits are recorded as an increase to additional paid-in capital. Conversely, a decrease in tax benefit (shortfall) is generated when the tax deduction is below the recorded deferred tax asset. This incremental expense results in additional income tax expense, unless it can be offset by accumulated windfall tax benefit recorded in additional paid-in capital. The gross windfall tax benefit is presented in the consolidated statements of cash flows as financing cash inflows.
	Performance-Based Long-Term Incentive Program
	On August 13, 2012, the Compensation Committee of the Board of Directors of the Company (the Compensation Committee) adopted a performance-based long-term incentive program (Performance-based Program) that provides for the issuance of two types of performance share units (PSUs).
	The Compensation Committee established performance goals under the Performance-based Program. Two types of PSUs may be awarded under the Performance-based Program: Book Value PSUs and Total Shareholder Return Units (TSR PSUs). The Book Value PSUs are eligible to vest based on the compound annualized growth in the Company’s book value per share (i.e., book value change with such adjustments as determined and approved by the Compensation Committee plus dividends on a reinvested basis) during the applicable performance period. The TSR PSUs are eligible to vest based on the Company’s compound annualized total shareholder return (i.e., share price change plus dividends on a reinvested basis) during the applicable performance period.
	On July 1, 2014, the Company granted an aggregate of 35,126 Book Value PSUs and 35,593 TSR PSUs to the participants in the Performance-based Program (2014 PSU Grants). For the 2014 PSU Grants, the Compensation Committee awarded PSUs with an aggregate grant date fair value equal to 100% of the participant’s base salary, with 50% of the total grant date fair value represented by Book Value PSUs and 50% of the total grant date fair value represented by TSR PSUs. The 2014 PSU Grants have a three-year performance period.
	The actual number of shares of Class A common stock that will be issued to each participant at the end of the applicable performance period will vary between 0% and 250% of the number of PSUs granted, depending on performance results. If the threshold level of performance goals are not achieved, no PSUs are earned. Participants will be eligible to receive 50% of the granted PSUs for Company performance at the threshold level, 100% of the granted PSUs for Company performance at the target level and 250% of the granted PSUs for Company performance at the maximum level, with linear interpolation for achievement falling between the performance levels. Shares of Class A common stock issued under a PSU will be issued pursuant to the 2011 Plan or the 2014 Plan, depending on the grant date of the PSU.
	The Company recorded $1,236 and $2,084, in compensation expenses related to the Performance-based Program during the three and nine months ended September 30, 2014, respectively. The Company recorded $398 and $915 in compensation expenses related to the Performance-based Program during the three and nine months ended September 30, 2013, respectively.
	Restricted Stock
	The following tables present the activities and balances related to restricted stock for the dates and periods indicated:
			Three Months Ended September 30,				Nine Months Ended September 30,
			2014		2013		2014		2013
	Shares granted			48,500		—		84,602		36,000
	Weighted-average share price		$	26.2	$	—	$	26.84	$	26.74
	Compensation expense recognized during the period		$	179	$	223	$	574	$	432
			30-Sep-14		31-Dec-13
	Restricted Class A shares outstanding, unvested			117,112		57,673
	Unrecognized compensation cost related to unvested shares		$	2,534	$	838
	Weighted-average vesting period remaining			2.13 years		2.04 years
	Conversion of Class B Common Stock to Class A Common Stock
	During the nine months ended September 30, 2014, a holder of the Company’s Class B common stock converted an aggregate of 104,827 shares of Class B common stock into 104,827 shares of Class A common stock. Holders of shares of Class A common stock are entitled to one vote for each share on all matters voted on by shareholders, and the holders of shares of Class B common stock are entitled to three votes per share on all matters voted on by shareholders. Under the Company’s Articles of Incorporation, shares of Class B common stock are convertible into shares of Class A common stock on a one-for-one basis.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
Recent Accounting Pronouncements	'
	8. Recent Accounting Pronouncements:
	On April 10, 2014, the FASB issued Accounting Standards Update (ASU) No. 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, which changes the criteria for determining which disposals can be presented as discontinued operations and modifies related disclosure requirements. This standard will be effective for the Company on January 1, 2015. The Company is currently evaluating the impact of ASU No. 2014-08.
	On May 28, 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, 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 No. 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 No. 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, 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 No. 2014-15.

Financial_Instruments_Tables

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2014
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:
			30-Sep-14						31-Dec-13
			Carrying Amount			Estimated			Carrying Amount			Estimated
						Fair Value						Fair Value
	Financial assets
	Cash and cash equivalents		$	31,093		$	31,093		$	48,628		$	48,628
	Interest receivable			9,259			9,259			5,173			5,173
	Other receivables			222			222			212			212
	MBS
	Agency-backed MBS			3,176,175			3,176,175			1,576,499			1,576,499
	Private-label MBS
	Senior securities			—			—			7,066			7,066
	Re-REMIC securities			292,809			292,809			334,233			334,233
	Derivative assets			8,966			8,966			8,424			8,424
	Other investments			1,891			1,891			2,065			2,065
	Deposits			95,216			95,216			45,504			45,504
	Financial liabilities
	Repurchase agreements			2,668,566			2,668,566			1,547,630			1,547,630
	Interest payable			901			901			774			774
	Long-term debt			40,000			39,380			40,000			36,620
	Derivative liabilities			67,410			67,410			33,129			33,129
	Purchased securities payable			263,425			263,425			—			—
	Accounts payable, accrued expenses and other liabilities			851			851			1,391			1,391
Fair Value Measurements, Recurring and Nonrecurring [Table Text Block]	'
	Financial Instruments Measured at Fair Value on a Recurring Basis
			30-Sep-14
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading
	Agency-backed MBS		$	3,176,135		$	—		$	3,176,135		$	—
	Available-for-sale
	Agency-backed MBS			40			—			40			—
	Private-label MBS
	Senior securities			—			—			—			—
	Re-REMIC securities			292,809			—			—			292,809
	Total available-for-sale			292,849			—			40			292,809
	Total MBS			3,468,984			—			3,176,175			292,809
	Derivative assets, at fair value			8,966			6,862			2,104			—
	Derivative liabilities, at fair value			(67,410	)		(67,347	)		(63	)		—
	Interest-only MBS, at fair value			220			—			—			220
	Total		$	3,410,760		$	(60,485	)	$	3,178,216		$	293,029
			31-Dec-13
			Total			Level 1			Level 2			Level 3
	MBS, at fair value
	Trading
	Agency-backed MBS		$	1,576,452		$	—		$	1,576,452		$	—
	Available-for-sale
	Agency-backed MBS			47			—			47			—
	Private-label MBS
	Senior securities			7,066			—			—			7,066
	Re-REMIC securities			334,233			—			—			334,233
	Total available-for-sale			341,346			—			47			341,299
	Total MBS			1,917,798			—			1,576,499			341,299
	Derivative assets, at fair value			8,424			8,088			336			—
	Derivative liabilities, at fair value			(33,129	)		(32,156	)		(973	)		—
	Interest-only MBS, at fair value			298			—			—			298
	Total		$	1,893,391		$	(24,068	)	$	1,575,862		$	341,597
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:
			30-Sep-14			31-Dec-13
	Original loan-to-value			68	%		69	%
	Original FICO score			723			725
	Three-month prepayment rate			12	%		14	%
	Three-month loss severities			42	%		37	%
	Weighted average coupon			2.98	%		3.34	%
Fair Value Inputs, Assets, Quantitative Information [Table Text Block]	'
	The significant unobservable inputs for the valuation model include the following weighted-averages, based on face value, as of the dates indicated:
			30-Sep-14						31-Dec-13
			Senior			Re-REMIC			Senior			Re-REMIC
			Securities(1)			Securities			Securities			Securities
	Discount rate			—	%		6.49	%		6	%		6.55	%
	Default rate			—	%		3.07	%		9.3	%		3.62	%
	Loss severity rate			—	%		42.04	%		50	%		44.82	%
	Prepayment rate			—	%		11.21	%		16.3	%		11.69	%
		-1	The Company did not own any senior securities on September 30, 2014.
	The ranges of the significant unobservable inputs for the valuation model were as follows as of the dates indicated:
			30-Sep-14						31-Dec-13
			Senior			Re-REMIC			Senior			Re-REMIC
			Securities(1)			Securities			Securities			Securities
	Discount rate			—	%		6.00 – 10.00	%		6	%		6.00 – 10.00	%
	Default rate			—	%		1.00 – 8.80	%		9.3	%		0.95 – 9.60	%
	Loss severity rate			—	%		29.24 – 57.50	%		50	%		29.15 – 57.50	%
	Prepayment rate			—	%		7.40 – 17.70	%		16.3	%		6.40 – 19.00	%
		-1	The Company did not own any senior securities on September 30, 2014.
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 and nine months ended September 30, 2014 and 2013.
			Three Months Ended September 30, 2014
			Senior			Re-REMIC			Total
			Securities			Securities
	Beginning balance, July 1, 2014		$	—		$	314,148		$	314,148
	Total net gains (losses)
	Included in earnings			—			3,475			3,475
	Included in other comprehensive income			—			(2,860	)		(2,860	)
	Purchases			—			—			—
	Sales			—			(25,044	)		(25,044	)
	Payments, net			—			(3,493	)		(3,493	)
	Accretion of discount			—			6,583			6,583
	Ending balance, September 30, 2014		$	—		$	292,809		$	292,809
	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		$	—		$	(71	)	$	(71	)
			Three Months Ended September 30, 2013
			Senior			Re-REMIC			Total
			Securities			Securities
	Beginning balance, July 1, 2013		$	7,246		$	321,674		$	328,920
	Total net gains (losses)
	Included in earnings			—			4,509			4,509
	Included in other comprehensive income			(117	)		72			(45	)
	Purchases			—			36,479			36,479
	Sales			—			(27,086	)		(27,086	)
	Payments, net			(313	)		(5,446	)		(5,759	)
	Accretion of discount			221			6,879			7,100
	Ending balance, September 30, 2013		$	7,037		$	337,081		$	344,118
	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		$	—		$	(380	)	$	(380	)
			Nine Months Ended September 30, 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			1,690			11,317			13,007
	Included in other comprehensive income			(1,654	)		(6,070	)		(7,724	)
	Purchases			—			—			—
	Sales			(7,029	)		(55,246	)		(62,275	)
	Payments, net			(319	)		(11,782	)		(12,101	)
	Accretion of discount			246			20,357			20,603
	Ending balance, September 30, 2014		$	—		$	292,809		$	292,809
	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		$	—		$	(122	)	$	(122	)
			Nine Months Ended September 30, 2013
			Senior			Re-REMIC			Total
			Securities			Securities
	Beginning balance, January 1, 2013		$	7,519		$	191,567		$	199,086
	Total net gains (losses)
	Included in earnings			—			12,299			12,299
	Included in other comprehensive income			(204	)		17,875			17,671
	Purchases			—			167,682			167,682
	Sales			—			(54,884	)		(54,884	)
	Payments, net			(950	)		(16,205	)		(17,155	)
	Accretion of discount			672			18,747			19,419
	Ending balance, September 30, 2013		$	7,037		$	337,081		$	344,118
	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		$	—		$	(1,270	)	$	(1,270	)
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 and nine months ended September 30, 2014 and 2013 are reported in the following statement of comprehensive income line descriptions:
			Other Loss, Investment Loss, net
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014			2013
	Total gains (losses) included in earnings for the period		$	3,475		$	4,509		$	13,007		$	12,299
	Change in unrealized gains (losses) relating to Level 3 assets still held at reporting date		$	(71	)	$	(380	)	$	(122	)	$	(1,270	)
Mortgage Backed Securities Fair Value [Table Text Block]	'
	MBS, at fair value(1)(2), consisted of the following as of the dates indicated:
			30-Sep-14														31-Dec-13
			Fair			Net Unamortized Premium (Discount)			Percent of Total			Weighted Average Life			Weighted Average Rating(3)		Fair		Net Unamortized Premium (Discount)			Percent of Total			Weighted Average Life		Weighted Average Rating(3)
			Value						Fair								Value					Fair
									Value													Value
	Trading
	Fannie Mae		$	1,883,424		$	—			54.3	%		8.9			AAA	$	997,488	$	—			52.01	%		9.4		AAA
	Freddie Mac			1,292,711			—			37.26	%		9.2			AAA		578,964		—			30.19	%		9.6		AAA
	Available-for-sale:
	Agency-backed
	Fannie Mae			40			—			—			5.3			AAA		47		—			—			5.8		AAA
	Private-label
	Senior securities			—			—			—			—			—		7,066		(4,789	)		0.37	%		4.8		C-
	Re-REMIC securities			292,809			(151,494	)		8.44	%		10.7			NR		334,233		(202,450	)		17.43	%		11.4		NR
			$	3,468,984		$	(151,494	)		100	%						$	1,917,798	$	(207,239	)		100	%
		-1	The Company’s MBS portfolio was primarily comprised of fixed-rate MBS at September 30, 2014 and December 31, 2013. The weighted-average interest rate of the MBS portfolio at September 30, 2014 and December 31, 2013 was 3.92% and 3.90%, respectively.
		-2	As of September 30, 2014 and December 31, 2013, the Company’s MBS investments with a fair value of $2,862,397 and $1,673,911, 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 and nine months ended September 30, 2014 and 2013:
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014			2013
	Beginning balance		$	291,128		$	317,695		$	326,330		$	207,853
	Accretion of discount			(6,583	)		(7,099	)		(20,602	)		(19,418	)
	Reclassifications, net			1,960			18,639			15,332			51,248
	Acquisitions			—			36,901			—			150,646
	Sales			(19,087	)		(27,372	)		(53,642	)		(51,565	)
	Ending balance		$	267,418		$	338,764		$	267,418		$	338,764
Schedule of Available for Sale Private Label MBS Acquired [Table Text Block]	'
	For the available-for-sale, private-label MBS acquired during the three and nine months ended September 30, 2014 and 2013, the contractually required payments receivable, the cash flow expected to be collected, and the fair value at the acquisition date were as follows for the dates indicated:
			Three Months Ended September 30,						Nine Months Ended September 30,
			2014			2013			2014			2013
	Contractually required payments receivable		$	—		$	87,640		$	—		$	420,500
	Cash flows expected to be collected			—			73,380			—			318,328
	Basis in acquired securities			—			36,479			—			167,682
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:
			30-Sep-14
			Amortized			Unrealized
			Cost/Cost
			Basis(1)			Gains			Losses			Fair Value
	Agency-backed MBS		$	36		$	4		$	—		$	40
	Private-label MBS
	Senior securities			—			—			—			—
	Re-REMIC securities			237,910			54,915			(16	)		292,809
	Total		$	237,946		$	54,919		$	(16	)	$	292,849
		-1	The amortized cost of MBS includes unamortized net discounts of $151,494 at September 30, 2014.
			31-Dec-13
			Amortized			Unrealized
			Cost/Cost
			Basis(1)			Gains			Losses			Fair Value
	Agency-backed MBS		$	43		$	4		$	—		$	47
	Private-label MBS
	Senior securities			5,412			1,654			—			7,066
	Re-REMIC securities			273,264			60,970			(1	)		334,233
	Total		$	278,719		$	62,628		$	(1	)	$	341,346
		-1	The amortized cost of MBS includes unamortized net discounts of $207,239 at December 31, 2013.
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Table Text Block]	'
	The following table presents a summary of other-than-temporary impairment charges included in earnings for the periods indicated and cumulative other-than-temporary impairment charges recognized on the MBS held as of the dates indicated:
			Three Months Ended September 30,						Nine Months Ended
									September 30,
			2014			2013			2014			2013
	Cumulative other-than-temporary impairment, beginning balance		$	19,687		$	23,283		$	23,663		$	23,768
	Additions
	Other-than-temporary impairments not previously recognized			—			380			122			380
	Increases related to other-than-temporary impairments on securities with previously recognized other-than-temporary impairments			71			—			—			890
	Reductions
	Decreases related to other-than-temporary impairments on sold securities			—			—			(4,027	)		(1,375	)
	Cumulative other-than-temporary impairment, ending balance		$	19,758		$	23,663		$	19,758		$	23,663
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 September 30,												Nine Months Ended September 30,
			2014						2013						2014				2013
			Agency-Backed			Private-Label			Agency-Backed			Private-Label			Agency-Backed		Private-Label		Agency-Backed			Private- Label
			MBS			MBS			MBS			MBS			MBS		MBS		MBS			MBS
	Proceeds from sales		$	65,251		$	25,044		$	309,518		$	27,085		$	65,251	$	62,275	$	837,257		$	54,884
	Gross gains			—			3,467			238			4,778			1,351		12,826		531			13,267
	Gross losses			218			—			4,118			—			—		—		26,469			—
Investment [Table Text Block]	'
	The Company’s other investments consisted of the following as of the dates indicated:
			30-Sep-14			31-Dec-13
	Interest-only MBS		$	220		$	298
	Non-public equity securities			975			975
	Investment funds			696			792
	Total other investments		$	1,891		$	2,065

Borrowings_Tables

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2014
Debt Disclosure [Abstract]	'
Schedule of Repurchase Agreements [Table Text Block]	'
	The following tables provide information regarding the Company’s outstanding repurchase agreement borrowings as of the dates and for the periods indicated:
			30-Sep-14			31-Dec-13
	Outstanding balance		$	2,668,566		$	1,547,630
	Value of assets pledged as collateral
	Agency-backed MBS			2,748,052			1,556,763
	Private-label MBS			114,345			117,148
	Net amount(1)			193,831			126,281
	Weighted-average rate			0.36	%		0.45	%
	Weighted-average term to maturity			14.0 days			13.2 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.
			30-Sep-14			30-Sep-13
	Weighted-average outstanding balance during the three months ended		$	2,658,695		$	1,581,663
	Weighted-average rate during the three months ended			0.36	%		0.44	%
	Weighted-average outstanding balance during the nine months ended		$	2,213,501		$	1,504,878
	Weighted-average rate during the nine months ended			0.37	%		0.44	%
Schedule of Long-term Debt Instruments [Table Text Block]	'
	The Company’s long-term debentures consisted of the following as of the dates indicated:
			30-Sep-14						31-Dec-13
			Senior			Trust			Senior		Trust
			Notes			Preferred Debt			Notes		Preferred Debt
	Outstanding Principal		$	25,000		$	15,000		$	25,000	$	15,000
	Annual Interest Rate			6.63%			LIBOR +			6.63%		LIBOR +
							2.25 – 3.00%					2.25 – 3.00%
	Interest Payment Frequency			Quarterly			Quarterly			Quarterly		Quarterly
	Weighted-Average Interest Rate			6.63%			2.98%			6.63%		2.99%
	Maturity			1-May-23			2033 – 2035			1-May-23		2033 – 2035
	Early Redemption Date			1-May-16			2008 – 2010			1-May-16		2008 – 2010

Derivative_Financial_Instrumen1

Derivative Financial Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2014
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:
			30-Sep-14					31-Dec-13
			Notional		Fair Value			Notional		Fair Value
			Amount					Amount
	No hedge designation
	Eurodollar futures
	Derivative assets		$	10,208,000	$	3,111		$	8,758,000	$	4,361
	Derivative liabilities			27,752,000		(44,062	)		6,787,000		(30,638	)
	Total Eurodollar futures(1)			37,960,000		(40,951	)		15,545,000		(26,277	)
	10-year swap futures
	Derivative assets			670,000		3,751			635,500		3,727
	Derivative liabilities			460,000		(23,285	)		31,000		(18	)
	Total 10-year swap futures(2)			1,130,000		(19,534	)		666,500		3,709
	5-year U.S. Treasury note futures			—		—			100,000		(1,500	)
	Commitment to purchase MBS(3)			497,569		2,104			169,511		(973	)
	Commitment to sell MBS(4)			50,000		(63	)		125,000		336
		-1	The $37,960,000 total notional amount of Eurodollar futures contracts as of September 30, 2014 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2014 and 2019. As of September 30, 2014, the Company maintained $57,970 as a deposit and margin against the open Eurodollar futures contracts.
		-2	The $1,130,000 represents the total notional amount of 10-year swap futures as of September 30, 2014, of which $765,000 of notional amount matures in December 2014 and $365,000 in notional amount matures in March 2024. As of September 30, 2014, the Company maintained $37,246 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.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2014
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 September 30,
		2014				2013
	(Shares in thousands)	Basic		Diluted		Basic		Diluted
	Weighted-average shares outstanding
	Common stock		20,577		20,577		16,669		16,669
	Stock options, performance share units, and unvested restricted stock		—		478		—		176
	Weighted-average common and common equivalent shares outstanding		20,577		21,055		16,669		16,845
	Net income applicable to common stock	$	12,847	$	12,847	$	3,093	$	3,093
	Net income per common share	$	0.62	$	0.61	$	0.19	$	0.18
		Nine Months Ended September 30,
		2014				2013
	(Shares in thousands)	Basic		Diluted		Basic		Diluted
	Weighted-average shares outstanding
	Common stock		19,056		19,056		15,761		15,761
	Stock options, performance share units, and unvested restricted stock		—		357		—		173
	Weighted-average common and common equivalent shares outstanding		19,056		19,413		15,761		15,934
	Net income applicable to common stock	$	38,719	$	38,719	$	9,464	$	9,464
	Net income per common share	$	2.03	$	1.99	$	0.6	$	0.59

Equity_Tables

Equity (Tables)	9 Months Ended
	Sep. 30, 2014
Equity [Abstract]	'
Equity Offerings [Table Text Block]	'
	During the nine months ended September 30, 2014, the Company completed two public offerings of its Class A Common Stock as follows:
	Closing date of the offering			28-Mar-14		8-Sep-14
	Shares sold to public			2,750,000		2,750,000
	Additional shares sold pursuant to the underwriter			312,500		412,500
	over-allotment option
	Total shares of Class A common stock sold in the offering			3,062,500		3,162,500
	Public offering price per share		$	27.4	$	27.61
	Net proceeds(1)		$	81,669	$	85,214
		-1	Net of underwriting discounts and commissions and expenses.
Schedule of Dividends Payable [Table Text Block]	'
	The Board of Directors has approved and the Company has declared the following dividends to date in 2014:
	Quarter Ended		Dividend Amount		Declaration Date		Record Date		Pay Date
	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
	The Board of Directors approved and the Company declared and paid the following dividends for 2013:
	Quarter Ended		Dividend Amount		Declaration Date		Record Date		Pay Date
	31-Dec		$	0.875		19-Dec		31-Dec		31-Jan-14
	30-Sep			0.875		18-Sep		30-Sep		31-Oct
	30-Jun			0.875		17-Jun		28-Jun		31-Jul
	31-Mar			0.875		15-Mar		28-Mar		30-Apr
Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]	'
	The following tables present the activities and balances related to restricted stock for the dates and periods indicated:
			Three Months Ended September 30,				Nine Months Ended September 30,
			2014		2013		2014		2013
	Shares granted			48,500		—		84,602		36,000
	Weighted-average share price		$	26.2	$	—	$	26.84	$	26.74
	Compensation expense recognized during the period		$	179	$	223	$	574	$	432
			30-Sep-14		31-Dec-13
	Restricted Class A shares outstanding, unvested			117,112		57,673
	Unrecognized compensation cost related to unvested shares		$	2,534	$	838
	Weighted-average vesting period remaining			2.13 years		2.04 years

Financial_Instruments_Details

Financial Instruments (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financial assets, Carrying Amount	'	'
Cash and cash equivalents, Carrying Amount	$31,093	$48,628
Interest receivable, Carrying Amount	9,259	5,173
Other receivables, Carrying Amount	222	212
MBS, Carrying Amount	'	'
Agency-backed MBS, Carrying Amount	3,176,175	1,576,499
Private-label MBS, Carrying Amount	'	'
Senior securities, Carrying Amount	0	7,066
Re-REMIC securities, Carrying Amount	292,809	334,233
Derivative assets, Carrying Amount	8,966	8,424
Other Investments, Carrying Amount	1,891	2,065
Deposits, Carrying Amount	95,216	45,504
Financial liabilities, Carrying Amount	'	'
Repurchase agreements, Carrying Amount	2,668,566	1,547,630
Interest payable, Carrying Amount	901	774
Long-term debt, Carrying Amount	40,000	40,000
Derivative liabilities, Carrying Amount	67,410	33,129
Purchased securities payable, Carrying Amount	263,425	0
Accounts payable, accrued expenses and other liabilities, Carrying Amount	851	1,391
Financial assets, Estimated Fair Value	'	'
Cash and cash equivalents, Estimated Fair Value	31,093	48,628
Interest receivable, Estimated Fair Value	9,259	5,173
Other receivables, Estimated Fair Value	222	212
MBS, Estimated Fair Value	'	'
Agency-backed MBS, Estimated Fair Value	3,176,175	1,576,499
Private-label MBS, Estimated Fair Value	'	'
Senior securities, Estimated Fair Value	0	7,066
Re-REMIC securities, Estimated Fair Value	292,809	334,233
Derivative assets, Estimated Fair Value	8,966	8,424
Other investments, Estimated Fair Value	1,891	2,065
Deposits, Estimated Fair Value	95,216	45,504
Financial liabilities, Estimated Fair Value	'	'
Repurchase agreements, Estimated Fair Value	2,668,566	1,547,630
Interest payable, Estimated Fair Value	901	774
Long-term debt, Estimated Fair Value	39,380	36,620
Derivative liabilities, Estimated Fair Value	67,410	33,129
Purchased securities payable, Estimated Fair Value	263,425	0
Accounts payable, accrued expenses and other liabilities, Estimated Fair Value	$851	$1,391

Financial_Instruments_Details_

Financial Instruments (Details 1) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
MBS, at fair value	'	'
Trading, Agency-backed MBS	$3,176,135	$1,576,452
Available-for-sale	'	'
Agency-backed MBS	40	47
Private-label MBS	'	'
Senior securities	0	7,066
Re-REMIC securities	292,809	334,233
Total available-for-sale	292,849	341,346
Total MBS	3,468,984	1,917,798
Derivative assets, at fair value	8,966	8,424
Derivative liabilities, at fair value	-67,410	-33,129
Interest-only MBS, at fair value	220	298
Total	3,410,760	1,893,391
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	'	'
Senior securities	0	0
Re-REMIC securities	0	0
Total available-for-sale	0	0
Total MBS	0	0
Derivative assets, at fair value	6,862	8,088
Derivative liabilities, at fair value	-67,347	-32,156
Interest-only MBS, at fair value	0	0
Total	-60,485	-24,068
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]	'	'
MBS, at fair value	'	'
Trading, Agency-backed MBS	3,176,135	1,576,452
Available-for-sale	'	'
Agency-backed MBS	40	47
Private-label MBS	'	'
Senior securities	0	0
Re-REMIC securities	0	0
Total available-for-sale	40	47
Total MBS	3,176,175	1,576,499
Derivative assets, at fair value	2,104	336
Derivative liabilities, at fair value	-63	-973
Interest-only MBS, at fair value	0	0
Total	3,178,216	1,575,862
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	'	'
Senior securities	0	7,066
Re-REMIC securities	292,809	334,233
Total available-for-sale	292,809	341,299
Total MBS	292,809	341,299
Derivative assets, at fair value	0	0
Derivative liabilities, at fair value	0	0
Interest-only MBS, at fair value	220	298
Total	$293,029	$341,597

Financial_Instruments_Details_1

Financial Instruments (Details 2)	Sep. 30, 2014	Dec. 31, 2013
	Scores	Scores
Underlying Collateral Quantitative Disclosures [Line Items]	'	'
Original loan-to-value	68.00%	69.00%
Original FICO score	723	725
Three-month prepayment rate	12.00%	14.00%
Three-month loss severities	42.00%	37.00%
Weighted average coupon	2.98%	3.34%

Financial_Instruments_Details_2

Financial Instruments (Details 3)	9 Months Ended		12 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Senior Securities [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Discount rate	0.00%	[1]	6.00%
Default rate	0.00%	[1]	9.30%
Loss severity rate	0.00%	[1]	50.00%
Prepayment rate	0.00%	[1]	16.30%
Re-REMIC Securities [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Discount rate	6.49%		6.55%
Default rate	3.07%		3.62%
Loss severity rate	42.04%		44.82%
Prepayment rate	11.21%		11.69%
Re-REMIC Securities [Member] | Maximum [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Discount rate	10.00%		10.00%
Default rate	8.80%		9.60%
Loss severity rate	57.50%		57.50%
Prepayment rate	17.70%		19.00%
Re-REMIC Securities [Member] | Minimum [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Discount rate	6.00%		6.00%
Default rate	1.00%		0.95%
Loss severity rate	29.24%		29.15%
Prepayment rate	7.40%		6.40%
[1]	The Company did not own any senior securities on September 30, 2014.

Financial_Instruments_Details_3

Financial Instruments (Details 4) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'
Beginning balance	$314,148	$328,920	$341,299	$199,086
Total net gains (losses)	'	'	'	'
Included in earnings	3,475	4,509	13,007	12,299
Included in other comprehensive income	-2,860	-45	-7,724	17,671
Purchases	0	36,479	0	167,682
Sales	-25,044	-27,086	-62,275	-54,884
Payments, net	-3,493	-5,759	-12,101	-17,155
Accretion of discount	6,583	7,100	20,603	19,419
Ending balance	292,809	344,118	292,809	344,118
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	-71	-380	-122	-1,270
Senior Securities [Member]	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'
Beginning balance	0	7,246	7,066	7,519
Total net gains (losses)	'	'	'	'
Included in earnings	0	0	1,690	0
Included in other comprehensive income	0	-117	-1,654	-204
Purchases	0	0	0	0
Sales	0	0	-7,029	0
Payments, net	0	-313	-319	-950
Accretion of discount	0	221	246	672
Ending balance	0	7,037	0	7,037
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	0	0
Re-REMIC Securities [Member]	'	'	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'
Beginning balance	314,148	321,674	334,233	191,567
Total net gains (losses)	'	'	'	'
Included in earnings	3,475	4,509	11,317	12,299
Included in other comprehensive income	-2,860	72	-6,070	17,875
Purchases	0	36,479	0	167,682
Sales	-25,044	-27,086	-55,246	-54,884
Payments, net	-3,493	-5,446	-11,782	-16,205
Accretion of discount	6,583	6,879	20,357	18,747
Ending balance	292,809	337,081	292,809	337,081
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	($71)	($380)	($122)	($1,270)

Financial_Instruments_Details_4

Financial Instruments (Details 5) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Gains and losses included in earnings [Abstract]	'	'	'	'
Total gains (losses) included in earnings for the period	$3,475	$4,509	$13,007	$12,299
Change in unrealized gains (losses) relating to Level 3 assets still held at reporting date	($71)	($380)	($122)	($1,270)

Financial_Instruments_Details_5

Financial Instruments (Details 6) (USD $)	9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Fair Value	$3,468,984	[1],[2]	$1,917,798	[1],[2]
Net Unamortized Premium (Discount)	-151,494		-207,239
Percentage of Total Fair Value	100.00%		100.00%
Trading, Fannie Mae [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Fair Value	1,883,424	[1],[2]	997,488	[1],[2]
Net Unamortized Premium (Discount)	0		0
Percentage of Total Fair Value	54.30%		52.01%
Weighted Average Life	'8 years 10 months 24 days		'9 years 4 months 24 days
Weighted Average Rating	'AAA	[3]	'AAA	[3]
Trading, Freddie Mac [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Fair Value	1,292,711	[1],[2]	578,964	[1],[2]
Net Unamortized Premium (Discount)	0		0
Percentage of Total Fair Value	37.26%		30.19%
Weighted Average Life	'9 years 2 months 12 days		'9 years 7 months 6 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	40	[1],[2]	47	[1],[2]
Net Unamortized Premium (Discount)	0		0
Percentage of Total Fair Value	0.00%		0.00%
Weighted Average Life	'5 years 3 months 18 days		'5 years 9 months 18 days
Weighted Average Rating	'AAA	[3]	'AAA	[3]
Private-label, Senior Securities [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Fair Value	0	[1],[2]	7,066	[1],[2]
Net Unamortized Premium (Discount)	0		-4,789
Percentage of Total Fair Value	0.00%		0.37%
Weighted Average Life	'0 years		'4 years 9 months 18 days
Weighted Average Rating	'—	[3]	'C-	[3]
Private-label, Re-REMIC Securities [Member]	'		'
Fair Value Inputs Assets Quantitative Information [Line Items]	'		'
Fair Value	292,809	[1],[2]	334,233	[1],[2]
Net Unamortized Premium (Discount)	($151,494)		($202,450)
Percentage of Total Fair Value	8.44%		17.43%
Weighted Average Life	'10 years 8 months 12 days		'11 years 4 months 24 days
Weighted Average Rating	'NR	[3]	'NR	[3]
[1]	The Companybs MBS portfolio was primarily comprised of fixed-rate MBS at September 30, 2014 and December 31, 2013. The weighted-average interest rate of the MBS portfolio at September 30, 2014 and December 31, 2013 was 3.92% and 3.90%, respectively.
[2]	As of September 30, 2014 and December 31, 2013, the Companybs MBS investments with a fair value of $2,862,397 and $1,673,911, 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		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'
Beginning balance	$291,128	$317,695	$326,330	$207,853
Accretion of discount	-6,583	-7,099	-20,602	-19,418
Reclassifications, net	1,960	18,639	15,332	51,248
Acquisitions	0	36,901	0	150,646
Sales	-19,087	-27,372	-53,642	-51,565
Ending balance	$267,418	$338,764	$267,418	$338,764

Financial_Instruments_Details_7

Financial Instruments (Details 8) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'	'	'	'
Contractually required payments receivable	$0	$87,640	$0	$420,500
Cash flows expected to be collected	0	73,380	0	318,328
Basis in acquired securities	$0	$36,479	$0	$167,682

Financial_Instruments_Details_8

Financial Instruments (Details 9) (USD $)	9 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost/Cost Basis	$237,946	[1]	$278,719	[2]
Unrealized Gains	54,919		62,628
Unrealized Losses	-16		-1
Fair Value	292,849		341,346
Agency Backed MBS [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost/Cost Basis	36	[1]	43	[2]
Unrealized Gains	4		4
Unrealized Losses	0		0
Fair Value	40		47
Private-label MBS Senior Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost/Cost Basis	0	[1]	5,412	[2]
Unrealized Gains	0		1,654
Unrealized Losses	0		0
Fair Value	0		7,066
Private-label MBS Re-REMIC Securities [Member]	'		'
Schedule of Available-for-sale Securities [Line Items]	'		'
Amortized Cost/Cost Basis	237,910	[1]	273,264	[2]
Unrealized Gains	54,915		60,970
Unrealized Losses	-16		-1
Fair Value	$292,809		$334,233
[1]	The amortized cost of MBS includes unamortized net discounts of $151,494 at September 30, 2014.
[2]	The amortized cost of MBS includes unamortized net discounts of $207,239 at December 31, 2013.

Financial_Instruments_Details_9

Financial Instruments (Details 10) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]	'	'	'	'
Cumulative other-than-temporary impairment, beginning balance	$19,687	$23,283	$23,663	$23,768
Additions	'	'	'	'
Other-than-temporary impairments not previously recognized	0	380	122	380
Increases related to other-than-temporary impairments on securities with previously recognized other-than-temporary impairments	71	0	0	890
Reductions	'	'	'	'
Decreases related to other-than-temporary impairments on sold securities	0	0	-4,027	-1,375
Cumulative other-than-temporary impairment, ending balance	$19,758	$23,663	$19,758	$23,663

Recovered_Sheet1

Financial Instruments (Details 11) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Agency Backed MBS [Member]	'	'	'	'
Proceeds from Sales of Mortgage Backed Securities [Line Items]	'	'	'	'
Proceeds from sales	$65,251	$309,518	$65,251	$837,257
Gross gains	0	238	1,351	531
Gross losses	218	4,118	0	26,469
Private label MBS [Member]	'	'	'	'
Proceeds from Sales of Mortgage Backed Securities [Line Items]	'	'	'	'
Proceeds from sales	25,044	27,085	62,275	54,884
Gross gains	3,467	4,778	12,826	13,267
Gross losses	$0	$0	$0	$0

Recovered_Sheet2

Financial Instruments (Details 12) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]	'	'
Interest-only MBS	$220	$298
Non-public equity securities	975	975
Investment funds	696	792
Total other investments	$1,891	$2,065

Recovered_Sheet3

Financial Instruments (Details Textual) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Fair Value Inputs Assets Quantitative Information [Line Items]	'	'	'	'	'
Percentage of Total Asset Measured and Reported at Fair Value, Recurring Basis	7.78%	'	7.78%	'	15.56%
Company's Interest in Non Public Equity Securities and Investment Funds	$1,671	'	$1,671	'	$1,767
Fair Value Measured on Nonrecurring Basis, Gain (Loss) Included in Earnings	'	'	'	138	'
Weighted Average Coupon Rate for MBS Portfolio	3.92%	'	3.92%	'	3.90%
Pledged Assets Separately Reported, Securities Pledged as Collateral, at Fair Value	2,862,397	'	2,862,397	'	1,673,911
Financial Instrument Unamortized Discount Premium Net	151,494	'	151,494	'	207,239
Other than Temporary Impairment Losses MBS	71	380	122	1,270	'
Cost Basis MBS Prior to Other than Temporary Impairment	$2,139	$10,104	$2,174	$11,688	'

Borrowings_Details

Borrowings (Details) (USD $)	3 Months Ended			9 Months Ended			12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Repurchase Agreement Counterparty [Line Items]	'		'	'		'	'
Outstanding balance	$2,668,566		'	$2,668,566		'	$1,547,630
Value of assets pledged as collateral	'		'	'		'	'
Net amount	193,831	[1]	'	193,831	[1]	'	126,281	[1]
Weighted-average rate	0.36%		'	0.36%		'	0.45%
Weighted-average term to maturity (in days)	'		'	'14.0 days		'	'13.2 days
Weighted-average outstanding balance	2,658,695		1,581,663	2,213,501		1,504,878	'
Weighted-average rate	0.36%		0.44%	0.37%		0.44%	'
Agency Backed MBS [Member]	'		'	'		'	'
Value of assets pledged as collateral	'		'	'		'	'
Value of assets pledged as collateral	2,748,052		'	2,748,052		'	1,556,763
Private label MBS [Member]	'		'	'		'	'
Value of assets pledged as collateral	'		'	'		'	'
Value of assets pledged as collateral	$114,345		'	$114,345		'	$117,148
[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 $)	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
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	2.98%	2.99%
Maturity	'2033 – 2035	'2033 – 2035
Early Redemption Date	'2008 – 2010	'2008 – 2010
Senior Notes [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 $)	Sep. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'
Long-term Debt	$40,000	$40,000

Derivative_Financial_Instrumen2

Derivative Financial Instruments and Hedging Activities (Details) (USD $)	Sep. 30, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Derivative [Line Items]	'		'
Derivative assets, Fair Value	$8,966		$8,424
Derivative liabilities, Fair Value	-67,410		-33,129
No Hedge Designation [Member] | Eurodollar Futures Asset [Member]	'		'
Derivative [Line Items]	'		'
Derivative asset, Notional Amount	10,208,000		8,758,000
Derivative assets, Fair Value	3,111		4,361
No Hedge Designation [Member] | Eurodollar Futures Liabilities [Member]	'		'
Derivative [Line Items]	'		'
Derivative liabilities, Notional Amount	27,752,000		6,787,000
Derivative liabilities, Fair Value	-44,062		-30,638
No Hedge Designation [Member] | Eurodollar Futures [Member]	'		'
Derivative [Line Items]	'		'
Notional Amount	37,960,000	[1]	15,545,000	[1]
Fair Value	-40,951	[1]	-26,277	[1]
No Hedge Designation [Member] | 10-Year Swap Futures Asset [Member]	'		'
Derivative [Line Items]	'		'
Derivative asset, Notional Amount	670,000		635,500
Derivative assets, Fair Value	3,751		3,727
No Hedge Designation [Member] | 10-Year Swap Futures Liablities [Member]	'		'
Derivative [Line Items]	'		'
Derivative liabilities, Notional Amount	460,000		31,000
Derivative liabilities, Fair Value	-23,285		-18
No Hedge Designation [Member] | 10-Year Swap Futures [Member]	'		'
Derivative [Line Items]	'		'
Notional Amount	1,130,000	[2]	666,500	[2]
Fair Value	-19,534	[2]	3,709	[2]
No Hedge Designation [Member] | 5-year U.S. Treasury note futures [Member]	'		'
Derivative [Line Items]	'		'
Notional Amount	0		100,000
Fair Value	0		-1,500
No Hedge Designation [Member] | Commitment to Purchase MBS [Member]	'		'
Derivative [Line Items]	'		'
Notional Amount	497,569	[3]	169,511	[3]
Fair Value	2,104	[3]	-973	[3]
No Hedge Designation [Member] | Commitment to Sell MBS [Member]	'		'
Derivative [Line Items]	'		'
Notional Amount	50,000	[4]	125,000	[4]
Fair Value	($63)	[4]	$336	[4]
[1]	The $37,960,000 total notional amount of Eurodollar futures contracts as of September 30, 2014 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2014 and 2019. As of September 30, 2014, the Company maintained $57,970 as a deposit and margin against the open Eurodollar futures contracts.
[2]	The $1,130,000 represents the total notional amount of 10-year swap futures as of September 30, 2014, of which $765,000 of notional amount matures in December 2014 and $365,000 in notional amount matures in March 2024. As of September 30, 2014, the Company maintained $37,246 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.

Derivative_Financial_Instrumen3

Derivative Financial Instruments and Hedging Activities (Details Textual) (USD $)	3 Months Ended			9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Derivative [Line Items]	'		'	'		'	'
Deposit Assets	$95,216		'	$95,216		'	$45,504
Gain (Loss) on Derivative Instruments, Net, Pretax	7,556		-14,457	-62,509		44,577	'
Eurodollar Futures [Member]	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Deposit Assets	57,970		'	57,970		'	'
Eurodollar Futures [Member] | No Hedge Designation [Member]	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Notional Amount	37,960,000	[1]	'	37,960,000	[1]	'	15,545,000	[1]
10-Year Swap Futures [Member]	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Deposit Assets	37,246		'	37,246		'	'
10-Year Swap Futures [Member] | No Hedge Designation [Member]	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Notional Amount	1,130,000	[2]	'	1,130,000	[2]	'	666,500	[2]
10-Year Swap Futures [Member] | No Hedge Designation [Member] | Matures In March 2024 [Member]	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Notional Amount	365,000		'	365,000		'	'
10-Year Swap Futures [Member] | No Hedge Designation [Member] | Matures In December 2014 [Member]	'		'	'		'	'
Derivative [Line Items]	'		'	'		'	'
Notional Amount	$765,000		'	$765,000		'	'
[1]	The $37,960,000 total notional amount of Eurodollar futures contracts as of September 30, 2014 represents the accumulation of Eurodollar futures contracts that mature on a quarterly basis between 2014 and 2019. As of September 30, 2014, the Company maintained $57,970 as a deposit and margin against the open Eurodollar futures contracts.
[2]	The $1,130,000 represents the total notional amount of 10-year swap futures as of September 30, 2014, of which $765,000 of notional amount matures in December 2014 and $365,000 in notional amount matures in March 2024. As of September 30, 2014, the Company maintained $37,246 as a deposit and margin against the open 10-year swap futures contracts.

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Line Items]	'	'	'	'	'
Income Tax Provision (Benefit)	$5,442	$2,455	$21,996	$1,247	'
Income (Loss) before Income Taxes	18,289	5,548	60,715	10,711	'
Effective Income Tax Rate, Percent	'	'	36.20%	11.64%	'
Deferred Tax Assets, Net	$147,686	'	$147,686	'	$165,851

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basic	'	'	'	'
Weighted-average shares outstanding common stock (in shares)	20,577	16,669	19,056	15,761
Stock options, performance share units, and unvested restricted stock (in shares)	0	0	0	0
Weighted-average common and common equivalent shares outstanding (in shares)	20,577	16,669	19,056	15,761
Net income applicable to common stock	$12,847	$3,093	$38,719	$9,464
Net income per common share (in dollars per share)	$0.62	$0.19	$2.03	$0.60
Diluted	'	'	'	'
Weighted-average shares outstanding common stock (in shares)	20,577	16,669	19,056	15,761
Stock options, performance share units, and unvested restricted stock (in shares)	478	176	357	173
Weighted-average common and common equivalent shares outstanding (in shares)	21,055	16,845	19,413	15,934
Net income applicable to common stock	$12,847	$3,093	$38,719	$9,464
Net income per common share (in dollars per share)	$0.61	$0.18	$1.99	$0.59

Earnings_Per_Share_Details_Tex

Earnings Per Share (Details Textual)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	38,646	43,598	29,543	23,796

Equity_Details

Equity (Details) (USD $)	9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014
Public offering one [Member]	'
Equity Offerings [Line Items]	'
Closing date of the offering	28-Mar-14
Shares sold to public (in shares)	2,750,000
Additional Shares sold pursuant to the underwriter over-allotment option (in shares)	312,500
Total shares of Class A common stock sold in the offering (in shares)	3,062,500
Public offering price per share (in dollars per share)	$27.40
Net proceeds	$81,669	[1]
Public offering two [Member]	'
Equity Offerings [Line Items]	'
Closing date of the offering	8-Sep-14
Shares sold to public (in shares)	2,750,000
Additional Shares sold pursuant to the underwriter over-allotment option (in shares)	412,500
Total shares of Class A common stock sold in the offering (in shares)	3,162,500
Public offering price per share (in dollars per share)	$27.61
Net proceeds	$85,214	[1]
[1]	Net of underwriting discounts and commissions and expenses.

Equity_Details_1

Equity (Details 1) (USD $)	3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Dividends Payable [Line Items]	'	'	'	'	'	'	'
Dividend Amount (in dollars per share)	$0.88	$0.88	$0.88	$0.88	$0.88	$0.88	$0.88
Declaration Date	17-Sep-14	11-Jun-14	13-Mar-14	19-Dec-13	18-Sep-13	17-Jun-13	15-Mar-13
Record Date	29-Sep-14	30-Jun-14	31-Mar-14	31-Dec-13	30-Sep-13	28-Jun-13	28-Mar-13
Pay Date	31-Oct-14	31-Jul-14	30-Apr-14	31-Jan-14	31-Oct-13	31-Jul-13	30-Apr-13

Equity_Details_2

Equity (Details 2) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Shares granted (in shares)	48,500	0	84,602	36,000	'
Weighted-average share price (in dollars per share)	$26.20	$0	$26.84	$26.74	'
Compensation expense recognized during the period	$179	$223	$574	$432	'
Restricted Class A shares outstanding, unvested (in shares)	117,112	'	117,112	'	57,673
Unrecognized compensation cost related to unvested shares	$2,534	'	$2,534	'	$838
Weighted-average vesting period remaining	'	'	'2 years 1 month 17 days	'	'2 years 14 days

Equity_Details_Textual

Equity (Details Textual) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

9 Months Ended

In Thousands, except Share data, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Apr. 07, 2014

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Book Value PSUs [Member]

Total Shareholder Units PSUs [Member]

Long Term Incentive Plan 2014 [Member]

Long Term Incentive Plan 2014 [Member]

Long Term Incentive Plan 2014 [Member]

Long Term Incentive Plan 2014 [Member]

Long Term Incentive Plan 2014 [Member]

Long Term Incentive Plan 2011 [Member]

Long Term Incentive Plan 2011 [Member]

Common Class A [Member]

Common Class A [Member]

Common Class B [Member]

Common Stock [Member]

Long Term Incentive Plan 2014 [Member]

Common Stock [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized

'

'

'

'

'

'

'

'

'

'

2,000,000

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant

'

'

'

'

'

'

'

'

'

'

'

308,934

443,504

'

1,998,774

'

Allocated Share-based Compensation Expense

$179

$223

$574

$432

'

'

$1,236

$398

$2,084

$915

'

'

'

'

'

'

Stock Issued During Period, Shares, Conversion of Convertible Securities

'

'

'

'

'

'

'

'

'

'

'

'

'

104,827

'

-104,827

Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross

'

'

'

'

35,126

35,593

'

'

'

'

'

'

'

'

'

'