Accounting Policies - Accounting Policies (Policies)	3 Months Ended
Accounting Policies - Accounting Policies (Policies)	Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Account Policies	ACCOUNTING POLICIES The interim unaudited consolidated financial statements of the Federal Agricultural Mortgage Corporation ("Farmer Mac") and subsidiaries have been prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission ("SEC"). These interim unaudited consolidated financial statements reflect all normal and recurring adjustments that are, in the opinion of management, necessary to present a fair statement of the financial position and the results of operations and cash flows of Farmer Mac and subsidiaries for the interim periods presented. Certain information and footnote disclosures normally included in the annual consolidated financial statements have been omitted as permitted by SEC rules and regulations. The December 31, 2014 consolidated balance sheet presented in this report has been derived from Farmer Mac's audited 2014 consolidated financial statements. Management believes that the disclosures are adequate to present fairly the consolidated financial statements as of the dates and for the periods presented. These interim unaudited consolidated financial statements should be read in conjunction with the 2014 consolidated financial statements of Farmer Mac and subsidiaries included in Farmer Mac's Annual Report on Form 10-K for the year ended December 31, 2014 filed with the SEC on March 16, 2015. That Form 10-K describes Farmer Mac's significant accounting policies, which include its policies on Principles of Consolidation; Cash and Cash Equivalents and Statements of Cash Flows; Transfers of Financial Assets and Liabilities; Investment Securities, Farmer Mac Guaranteed Securities, and USDA Securities; Loans; Securitization of Loans; Real Estate Owned; Financial Derivatives; Notes Payable; Allowance for Loan Losses and Reserve for Losses; Earnings Per Common Share; Income Taxes; Stock-Based Compensation; Comprehensive Income; Long-Term Standby Purchase Commitments; Fair Value Measurement; and Consolidation of Variable Interest Entities ("VIEs"). Results for interim periods are not necessarily indicative of those that may be expected for the fiscal year. Presented below are Farmer Mac's significant accounting policies that contain updated information for the three months ended March 31, 2015.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Farmer Mac and its three subsidiaries: (1) Farmer Mac Mortgage Securities Corporation ("FMMSC"), whose principal activities are to facilitate the purchase and issuance of Farmer Mac Guaranteed Securities; (2) Farmer Mac II LLC, whose principal activity is the operation of substantially all of the business related to the USDA Guarantees line of business – primarily the acquisition of USDA Securities; and (3) Contour Valuation Services, LLC, whose principal activity is to provide appraisal services related to agricultural real estate. All inter-company balances and transactions have been eliminated in consolidation. The consolidated financial statements also include the accounts of VIEs in which Farmer Mac determined itself to be the primary beneficiary.
Cash and Cash Equivalents and Statements of Cash Flows	Statements of Cash Flows
Earnings Per Common Share	Earnings Per Common Share Basic earnings per common share ("EPS") is based on the weighted-average number of shares of common stock outstanding. Diluted earnings per common share is based on the weighted-average number of shares of common stock outstanding adjusted to include all potentially dilutive common stock options, stock appreciation rights ("SARs"), and non-vested restricted stock awards.
New Accounting Standards	New Accounting Standards In February 2015, the FASB issued ASU 2015-02, "Amendments to the Consolidation Analysis." This update modifies the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities and eliminates the presumption that a general partner should consolidate a limited partnership. It also affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships. ASU 2015-02 is effective for interim and annual periods beginning after December 15, 2015. The adoption of the new guidance will not have a material effect on Farmer Mac's financial position, results of operations, or cash flows.
Reclassifications	Reclassifications Beginning January 1, 2015, Farmer Mac classified all of the income from Farmer Mac Guaranteed Securities that it holds in its portfolio as interest income. Prior to January 1, 2015, Farmer Mac classified a portion of the income from those securities, $2.7 million in first quarter 2014, as guarantee and commitment fees. This change in classification does not affect the timing or amount of income recognized from these securities. The corresponding guarantee and commitment fee receivable balance as of December 31, 2014 also was reclassified to accrued interest receivable. Certain reclassifications of prior period information, including the aforementioned change, were made to conform to the current period presentation.

Disclosure of accounting policy for cash and cash equivalents, including the policy for determining which items are treated as cash equivalents. Other information that may be disclosed includes (1) the nature of any restrictions on the entity's use of its cash and cash equivalents, (2) whether the entity's cash and cash equivalents are insured or expose the entity to credit risk, (3) the classification of any negative balance accounts (overdrafts), and (4) the carrying basis of cash equivalents (for example, at cost) and whether the carrying amount of cash equivalents approximates fair value.

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- Definition

Disclosure of accounting policy regarding (1) the principles it follows in consolidating or combining the separate financial statements, including the principles followed in determining the inclusion or exclusion of subsidiaries or other entities in the consolidated or combined financial statements and (2) its treatment of interests (for example, common stock, a partnership interest or other means of exerting influence) in other entities, for example consolidation or use of the equity or cost methods of accounting. The accounting policy may also address the accounting treatment for intercompany accounts and transactions, noncontrolling interest, and the income statement treatment in consolidation for issuances of stock by a subsidiary.

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- Definition

Disclosure of accounting policy for computing basic and diluted earnings or loss per share for each class of common stock and participating security. Addresses all significant policy factors, including any antidilutive items that have been excluded from the computation and takes into account stock dividends, splits and reverse splits that occur after the balance sheet date of the latest reporting period but before the issuance of the financial statements.

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