CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Interest Income:
Residential whole loans held at carrying value	$ 3,591	$ 0
Cash and cash equivalent investments	27	26
Interest Income	129,942	121,174
Interest Expense:
Repurchase agreements	41,182	36,729
Securitized debt	750us-gaap_InterestExpenseDebt	2,185us-gaap_InterestExpenseDebt
Senior Notes	2,008	2,007
Interest Expense	43,940us-gaap_InterestExpense	40,921us-gaap_InterestExpense
Net Interest Income	86,002us-gaap_InterestIncomeExpenseNet	80,253us-gaap_InterestIncomeExpenseNet
Other-Than-Temporary Impairments:
Total other-than-temporary impairment losses	(395)	0
Portion of loss reclassed from other comprehensive income	(12)	0
Net Impairment Losses Recognized in Earnings	(407)	0
Other Income, net:
Unrealized net gains and net interest income from Linked Transactions	0mfa_GainOnLinkedTransactions	3,251mfa_GainOnLinkedTransactions
Net income on residential whole loans held at fair value	2,576	0
Gain on sales of MBS	6,435	3,571
Other, net	26us-gaap_OtherNonoperatingIncomeExpense	(416)us-gaap_OtherNonoperatingIncomeExpense
Other Income, net	9,037us-gaap_NoninterestIncome	6,406us-gaap_NoninterestIncome
Operating and Other Expense:
Compensation and benefits	6,746us-gaap_LaborAndRelatedExpense	6,507us-gaap_LaborAndRelatedExpense
Other general and administrative expense	3,457	3,964
Other investment related operating expenses	2,256us-gaap_OtherCostAndExpenseOperating	0us-gaap_OtherCostAndExpenseOperating
Operating and Other Expense	12,459us-gaap_CostsAndExpenses	10,471us-gaap_CostsAndExpenses
Net Income	82,173us-gaap_NetIncomeLoss	76,188us-gaap_NetIncomeLoss
Less Preferred Stock Dividends	3,750	3,750
Net Income Available to Common Stock and Participating Securities	78,423	72,438
Earnings per Common Share - Basic and Diluted (in dollars per share)	$ 0.21us-gaap_EarningsPerShareBasicAndDiluted	$ 0.20us-gaap_EarningsPerShareBasicAndDiluted
Dividends Declared per Share of Common Stock (in dollars per share)	$ 0.20	$ 0.20
Agency Mortgage Backed Securities
Interest Income:
Securities	31,673	39,329
Non-Agency MBS
Interest Income:
Securities	73,761	81,778
Non-Agency MBS \| Non-Agency MBS
Interest Income:
Securities	81,248	43,155
Non-Agency MBS \| Non-Agency MBS Transferred to Consolidated VIEs
Interest Income:
Securities	12,043	38,664
CRT securities
Interest Income:
Securities	$ 1,360	$ 0

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Mortgage Loans on Real Estate, Gain (Loss) on Loans at Fair Value

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This item represents the difference between the gross realized gains and losses realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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Aggregate dividends declared during the period for each share of common stock outstanding.

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

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Interest and fee income from commercial and residential real estate loans.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation.

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Amount before tax of other than temporary impairment loss (OTTI) on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss and attributable to parent entity.

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