Summary Of Significant Accounting Policies (Policy)	12 Months Ended
Dec. 31, 2011
Summary Of Significant Accounting Policies [Abstract]
Basis Of Presentation And Use Of Estimates	Basis of Presentation and Use of Estimates The accompanying financial statements are prepared on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles ("GAAP"). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates affecting the accompanying financial statements include the valuation of MBS and derivative instruments.
Cash And Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less, and which are not restricted as to use, to be cash equivalents. The carrying amounts of cash equivalents approximate their fair value.
Restricted Cash	Restricted Cash Restricted cash is cash held in margin accounts at various counterparties to offset interest rate hedging liabilities.
Interest Income	Interest Income Interest income is earned and recognized based on the outstanding principal amount of the investment securities and their contractual terms. Premiums and discounts associated with the purchase of the investment securities are amortized or accreted into interest income over the actual lives of the securities using the effective interest method.
Financial Instruments	Financial Instruments The Company considers its cash and cash equivalents, restricted cash, MBS (settled and unsettled), forward purchase commitments, debt security held to maturity, accrued interest receivable, principal payment receivable, accounts payable, derivative instruments, repurchase agreements and accrued interest payable to meet the definition of financial instruments. The carrying amount of cash and cash equivalents, restricted cash, accrued interest receivable and accounts payable approximate their fair value due to the short maturities of these instruments. See Note 4 for discussion of the fair value of MBS and forward purchase commitments. See Note 5 for discussion of the fair value of the held to maturity debt security. See Note 7 for discussion of the fair value of derivatives. The carrying amount of the repurchase agreements and accrued interest payable is deemed to approximate fair value since the lines are based upon a variable rate of interest. Since inception through December 31, 2011, the Company has limited its exposure to credit losses on its portfolio of securities by purchasing MBS guaranteed by Fannie Mae and Freddie Mac. The portfolio is diversified to avoid undue exposure to loan originator, geographic and other types of concentration. The Company manages the risk of prepayments of the underlying mortgages by creating a diversified portfolio with a variety of prepayment characteristics. See Note 4 for additional information on MBS. The Company is engaged in various trading and brokerage activities including derivative interest rate swap agreements in which counterparties primarily include broker-dealers, banks, and other financial institutions. In the event counterparties do not fulfill their obligations, the Company may be exposed to risk of loss. The risk of default depends on the creditworthiness of the counterparty and/or issuer of the instrument. It is the Company's policy to review, as necessary, the credit standing for each counterparty. See Note 7 for additional information on interest rate swap agreements.
Mortgage-Backed Securities	Mortgage-Backed Securities The Company invests in Agency MBS representing interests in or obligations backed by pools of single-family adjustable-rate mortgage loans. Guidance under the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 820 on Investments requires the Company to classify its investments as either trading, available-for-sale or held-to-maturity securities. Management determines the appropriate classifications of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company currently classifies all of its Agency MBS as available-for-sale. All assets that are classified as available-for-sale are carried at fair value and unrealized gains and losses are included in other comprehensive income. The estimated fair values of MBS are determined by management by obtaining valuations for its MBS from independent sources and averaging these valuations. Security purchase and sale transactions are recorded on the trade date. Gains or losses realized from the sale of securities are included in income and are determined using the specific identification method. Firm purchase commitments to acquire "when issued" or to-be-announced ("TBA") securities are recorded at fair value in accordance with ASC Topic 815, Derivatives and Hedging. The fair value of these purchase commitments is included in other assets or liabilities in the accompanying balance sheets. The Company assesses its investment securities for other-than-temporary impairment on at least a quarterly basis. When the fair value of an investment is less than its amortized cost at the balance sheet date of the reporting period for which impairment is assessed, the impairment is designated as either "temporary" or "other-than-temporary." In deciding on whether or not a security is other than temporarily impaired, the Company uses a two step evaluation process. First, the Company determines whether it has made any decision to sell a security that is in an unrealized loss position, or, if not the Company determines whether it is more likely than not that the Company will be required to sell the security prior to recovering its amortized cost basis. If the answer to either of these questions is "yes" then the security is considered other-than-temporarily impaired. There were no such impairment losses recognized during the periods presented.
Repurchase Agreements	Repurchase Agreements The Company finances the acquisition of its Agency MBS through the use of repurchase agreements. Under these repurchase agreements, the Company sells securities to a lender and agrees to repurchase the same securities in the future for a price that is higher than the original sales price. The difference between the sale price that the Company receives and the repurchase price that the Company pays represents interest paid to the lender. Although structured as a sale and repurchase obligation, a repurchase agreement operates as a financing under which the Company pledges its securities as collateral to secure a loan which is equal in value to a specified percentage of the estimated fair value of the pledged collateral. The Company retains beneficial ownership of the pledged collateral. At the maturity of a repurchase agreement, the Company is required to repay the loan and concurrently receives back its pledged collateral from the lender or, with the consent of the lender, the Company may renew such agreement at the then prevailing financing rate. These repurchase agreements may require the Company to pledge additional assets to the lender in the event the estimated fair value of the existing pledged collateral declines.
Comprehensive Income	Comprehensive Income In accordance with the guidance included in ASC Topic 220 on Comprehensive Income, the Company early adopted the requirement to separately report its comprehensive income. Other comprehensive income refers to revenue, expenses, gains, and losses that are recorded directly as an adjustment to shareholders' equity. Other comprehensive income for the Company generally arises from unrealized gains or losses generated from changes in market values of the securities held as available-for-sale and derivative instruments.
Derivative Instruments	Derivative Instruments The Company accounts for derivative instruments in accordance with the guidance included in the ASC Topic on Derivatives and Hedging. This guidance establishes accounting and reporting standards for derivative instruments, including certain derivative instruments embedded in other contracts (collectively referred to as derivatives), and for hedging activities. The guidance requires that every derivative instrument be recorded in the balance sheet as either an asset or liability measured at its fair value, and that changes in the derivative's fair value be recognized currently in earnings unless specific hedge accounting criteria are met. Special accounting for qualifying hedges allows a derivative's gains and losses to either offset related results on the hedged item in the statement of income or be accumulated in other comprehensive income, and requires that a company formally document, designate, and assess the effectiveness of transactions that receive hedge accounting. The Company uses derivative instruments to manage its exposure to changing interest rates generally with interest rate swap agreements.
Income Taxes	Income Taxes The Company has elected to be taxed as a REIT under the Code. The Company will generally not be subject to Federal income tax to the extent that it distributes 100% of its taxable income, after application of available tax attributes, within the time limits prescribed by the Code and as long as it satisfies the ongoing REIT requirements including meeting certain asset, income and stock ownership tests.
Share-Based Compensation	Share-Based Compensation Share-based compensation is accounted for under the guidance included in the ASC Topic on Stock Compensation. For share and share-based awards issued to employees, a compensation charge is recorded in earnings based on the fair value of the award. For transactions with non-employees in which services are performed in exchange for the Company's common stock or other equity instruments, the transactions are recorded on the basis of the fair value of the service received or the fair value of the equity instruments issued, whichever is more readily measurable at the date of issuance. The Company's share-based compensation transactions resulted in compensation expense of $1,150, $1,432, and $1,296 for the years ended December 31, 2011 and 2010, and 2009, respectively.
Earnings Per Common Share (EPS)	Earnings Per Common Share (EPS) Basic EPS is computed by dividing net income available to holders of common stock by the weighted average number of shares of common stock outstanding during the period. Diluted EPS is computed using the two class method, as described in the ASC Topic on Earnings Per Share, which takes into account certain adjustments related to participating securities. Net income available to holders of common stock after deducting dividends on unvested participating securities if antidilutive, is divided by the weighted average shares of common stock and common equivalent shares outstanding during the period. For the diluted EPS calculation, common equivalent shares outstanding includes the weighted average number of shares of common stock outstanding adjusted for the effect of dilutive unexercised stock options.

Summary Of Significant Accounting Policies (Policy)

12 Months Ended

Dec. 31, 2011

Summary Of Significant Accounting Policies [Abstract]

Basis Of Presentation And Use Of Estimates

Basis of Presentation and Use of Estimates

The accompanying financial statements are prepared on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles ("GAAP"). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant estimates affecting the accompanying financial statements include the valuation of MBS and derivative instruments.

Cash And Cash Equivalents

Cash and Cash Equivalents

The Company considers all highly liquid investments with original maturities of three months or less, and which are not restricted as to use, to be cash equivalents. The carrying amounts of cash equivalents approximate their fair value.

Restricted Cash

Restricted Cash

Restricted cash is cash held in margin accounts at various counterparties to offset interest rate hedging liabilities.

Interest Income

Interest Income

Interest income is earned and recognized based on the outstanding principal amount of the investment securities and their contractual terms. Premiums and discounts associated with the purchase of the investment securities are amortized or accreted into interest income over the actual lives of the securities using the effective interest method.

Financial Instruments

Financial Instruments

The Company considers its cash and cash equivalents, restricted cash, MBS (settled and unsettled), forward purchase commitments, debt security held to maturity, accrued interest receivable, principal payment receivable, accounts payable, derivative instruments, repurchase agreements and accrued interest payable to meet the definition of financial instruments. The carrying amount of cash and cash equivalents, restricted cash, accrued interest receivable and accounts payable approximate their fair value due to the short maturities of these instruments. See Note 4 for discussion of the fair value of MBS and forward purchase commitments. See Note 5 for discussion of the fair value of the held to maturity debt security. See Note 7 for discussion of the fair value of derivatives. The carrying amount of the repurchase agreements and accrued interest payable is deemed to approximate fair value since the lines are based upon a variable rate of interest.

Since inception through December 31, 2011, the Company has limited its exposure to credit losses on its portfolio of securities by purchasing MBS guaranteed by Fannie Mae and Freddie Mac. The portfolio is diversified to avoid undue exposure to loan originator, geographic and other types of concentration. The Company manages the risk of prepayments of the underlying mortgages by creating a diversified portfolio with a variety of prepayment characteristics. See Note 4 for additional information on MBS.

The Company is engaged in various trading and brokerage activities including derivative interest rate swap agreements in which counterparties primarily include broker-dealers, banks, and other financial institutions. In the event counterparties do not fulfill their obligations, the Company may be exposed to risk of loss. The risk of default depends on the creditworthiness of the counterparty and/or issuer of the instrument. It is the Company's policy to review, as necessary, the credit standing for each counterparty. See Note 7 for additional information on interest rate swap agreements.

Mortgage-Backed Securities

Mortgage-Backed Securities

The Company invests in Agency MBS representing interests in or obligations backed by pools of single-family adjustable-rate mortgage loans. Guidance under the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 820 on Investments requires the Company to classify its investments as either trading, available-for-sale or held-to-maturity securities. Management determines the appropriate classifications of the securities at the time they are acquired and evaluates the appropriateness of such classifications at each balance sheet date. The Company currently classifies all of its Agency MBS as available-for-sale. All assets that are classified as available-for-sale are carried at fair value and unrealized gains and losses are included in other comprehensive income. The estimated fair values of MBS are determined by management by obtaining valuations for its MBS from independent sources and averaging these valuations. Security purchase and sale transactions are recorded on the trade date. Gains or losses realized from the sale of securities are included in income and are determined using the specific identification method. Firm purchase commitments to acquire "when issued" or to-be-announced ("TBA") securities are recorded at fair value in accordance with ASC Topic 815, Derivatives and Hedging. The fair value of these purchase commitments is included in other assets or liabilities in the accompanying balance sheets.

The Company assesses its investment securities for other-than-temporary impairment on at least a quarterly basis. When the fair value of an investment is less than its amortized cost at the balance sheet date of the reporting period for which impairment is assessed, the impairment is designated as either "temporary" or "other-than-temporary." In deciding on whether or not a security is other than temporarily impaired, the Company uses a two step evaluation process. First, the Company determines whether it has made any decision to sell a security that is in an unrealized loss position, or, if not the Company determines whether it is more likely than not that the Company will be required to sell the security prior to recovering its amortized cost basis. If the answer to either of these questions is "yes" then the security is considered other-than-temporarily impaired. There were no such impairment losses recognized during the periods presented.

Repurchase Agreements

Repurchase Agreements

The Company finances the acquisition of its Agency MBS through the use of repurchase agreements. Under these repurchase agreements, the Company sells securities to a lender and agrees to repurchase the same securities in the future for a price that is higher than the original sales price. The difference between the sale price that the Company receives and the repurchase price that the Company pays represents interest paid to the lender. Although structured as a sale and repurchase obligation, a repurchase agreement operates as a financing under which the Company pledges its securities as collateral to secure a loan which is equal in value to a specified percentage of the estimated fair value of the pledged collateral. The Company retains beneficial ownership of the pledged collateral. At the maturity of a repurchase agreement, the Company is required to repay the loan and concurrently receives back its pledged collateral from the lender or, with the consent of the lender, the Company may renew such agreement at the then prevailing financing rate. These repurchase agreements may require the Company to pledge additional assets to the lender in the event the estimated fair value of the existing pledged collateral declines.

Comprehensive Income

Comprehensive Income

In accordance with the guidance included in ASC Topic 220 on Comprehensive Income, the Company early adopted the requirement to separately report its comprehensive income. Other comprehensive income refers to revenue, expenses, gains, and losses that are recorded directly as an adjustment to shareholders' equity. Other comprehensive income for the Company generally arises from unrealized gains or losses generated from changes in market values of the securities held as available-for-sale and derivative instruments.

Derivative Instruments

Derivative Instruments

The Company accounts for derivative instruments in accordance with the guidance included in the ASC Topic on Derivatives and Hedging. This guidance establishes accounting and reporting standards for derivative instruments, including certain derivative instruments embedded in other contracts (collectively referred to as derivatives), and for hedging activities. The guidance requires that every derivative instrument be recorded in the balance sheet as either an asset or liability measured at its fair value, and that changes in the derivative's fair value be recognized currently in earnings unless specific hedge accounting criteria are met. Special accounting for qualifying hedges allows a derivative's gains and losses to either offset related results on the hedged item in the statement of income or be accumulated in other comprehensive income, and requires that a company formally document, designate, and assess the effectiveness of transactions that receive hedge accounting. The Company uses derivative instruments to manage its exposure to changing interest rates generally with interest rate swap agreements.

Income Taxes

Income Taxes

The Company has elected to be taxed as a REIT under the Code. The Company will generally not be subject to Federal income tax to the extent that it distributes 100% of its taxable income, after application of available tax attributes, within the time limits prescribed by the Code and as long as it satisfies the ongoing REIT requirements including meeting certain asset, income and stock ownership tests.

Share-Based Compensation

Share-Based Compensation

Share-based compensation is accounted for under the guidance included in the ASC Topic on Stock Compensation. For share and share-based awards issued to employees, a compensation charge is recorded in earnings based on the fair value of the award. For transactions with non-employees in which services are performed in exchange for the Company's common stock or other equity instruments, the transactions are recorded on the basis of the fair value of the service received or the fair value of the equity instruments issued, whichever is more readily measurable at the date of issuance. The Company's share-based compensation transactions resulted in compensation expense of $1,150, $1,432, and $1,296 for the years ended December 31, 2011 and 2010, and 2009, respectively.

Earnings Per Common Share (EPS)

Earnings Per Common Share (EPS)

Basic EPS is computed by dividing net income available to holders of common stock by the weighted average number of shares of common stock outstanding during the period. Diluted EPS is computed using the two class method, as described in the ASC Topic on Earnings Per Share, which takes into account certain adjustments related to participating securities. Net income available to holders of common stock after deducting dividends on unvested participating securities if antidilutive, is divided by the weighted average shares of common stock and common equivalent shares outstanding during the period. For the diluted EPS calculation, common equivalent shares outstanding includes the weighted average number of shares of common stock outstanding adjusted for the effect of dilutive unexercised stock options.