This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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Derivative instrument obligations meeting the definition of a liability which the Company is a party to as of the balance sheet date.

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Trading Securities which consist of all investments in certain debt and equity securities that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) or for which an entity has elected the fair value option. Trading generally reflects active and frequent buying and selling, and trading securities are generally used with the objective of generating profits on short-term differences in price, but this category of investments may also include items which are not intended to be sold in the near term or for which the fair value option has been elected.

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Fair Value Disclosures - Quantitative Information (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified										9 Months Ended																		9 Months Ended											9 Months Ended
	Sep. 30, 2012 Interactive Bids Auction-rate certificates backed by Government guaranteed student loans Floating Interest Rate [Member]	Sep. 30, 2012 Discounted Cash Flows	Sep. 30, 2012 Discounted Cash Flows Asset-backed Securities Floating Interest Rate [Member]	Sep. 30, 2012 Farmer Mac Guarantee Discounted Cash Flows Farmer Mac I Guaranteed Securities	Sep. 30, 2012 Farmer Mac Guarantee Discounted Cash Flows Farmer Mac II Guaranteed Securities	Sep. 30, 2012 Farmer Mac Guarantee Discounted Cash Flows Farmer Mac Guaranteed Securities - Rural Utilities	Sep. 30, 2012 Discounted Cash Flows	Sep. 30, 2012 Level 3	Dec. 31, 2011 Level 3	Sep. 30, 2012 Level 3 Interactive Bids Minimum Auction-rate certificates backed by Government guaranteed student loans Floating Interest Rate [Member]	Sep. 30, 2012 Level 3 Interactive Bids Maximum Auction-rate certificates backed by Government guaranteed student loans Floating Interest Rate [Member]	Sep. 30, 2012 Level 3 Interactive Bids Weighted Average Auction-rate certificates backed by Government guaranteed student loans Floating Interest Rate [Member]	Sep. 30, 2012 Level 3 Discounted Cash Flows Asset-backed Securities Floating Interest Rate [Member]	Sep. 30, 2012 Level 3 Discounted Cash Flows Minimum Derivative Financial Instruments, Liabilities [Member]	Sep. 30, 2012 Level 3 Discounted Cash Flows Minimum Asset-backed Securities Floating Interest Rate [Member]	Sep. 30, 2012 Level 3 Discounted Cash Flows Maximum Derivative Financial Instruments, Liabilities [Member]	Sep. 30, 2012 Level 3 Discounted Cash Flows Maximum Asset-backed Securities Floating Interest Rate [Member]	Sep. 30, 2012 Level 3 Discounted Cash Flows Weighted Average Derivative Financial Instruments, Liabilities [Member]	Sep. 30, 2012 Level 3 Discounted Cash Flows Weighted Average Asset-backed Securities Floating Interest Rate [Member]	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Farmer Mac Guaranteed Securities	Dec. 31, 2011 Level 3 Farmer Mac Guarantee Farmer Mac Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Farmer Mac I Guaranteed Securities	Dec. 31, 2011 Level 3 Farmer Mac Guarantee Farmer Mac I Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Farmer Mac II Guaranteed Securities	Dec. 31, 2011 Level 3 Farmer Mac Guarantee Farmer Mac II Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Farmer Mac Guaranteed Securities - Rural Utilities	Dec. 31, 2011 Level 3 Farmer Mac Guarantee Farmer Mac Guaranteed Securities - Rural Utilities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Minimum Farmer Mac I Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Minimum Farmer Mac II Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Minimum Farmer Mac Guaranteed Securities - Rural Utilities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Maximum Farmer Mac I Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Maximum Farmer Mac II Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Maximum Farmer Mac Guaranteed Securities - Rural Utilities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Weighted Average Farmer Mac I Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Weighted Average Farmer Mac II Guaranteed Securities	Sep. 30, 2012 Level 3 Farmer Mac Guarantee Discounted Cash Flows Weighted Average Farmer Mac Guaranteed Securities - Rural Utilities	Sep. 30, 2012 Level 3	Dec. 31, 2011 Level 3	Sep. 30, 2012 Level 3 Discounted Cash Flows Minimum	Sep. 30, 2012 Level 3 Discounted Cash Flows Maximum	Sep. 30, 2012 Level 3 Discounted Cash Flows Weighted Average
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Available-for-sale securities	$ 60,034			$ 3,431,588	$ 29,975	$ 1,186,944		$ 60,034	$ 60,213											$ 4,648,507	$ 4,289,272	$ 3,431,588	$ 2,807,627	$ 29,975	$ 35,599	$ 1,186,944	$ 1,446,046										$ 1,468,041	$ 1,279,546
Trading securities			1,344					1,344	1,796																												122,587	212,359
Marketable Securities							1,590,628	61,378	62,009																												1,590,628	1,491,905
Financial derivatives, Liabilities		$ 880						$ 880	$ 1,335
Range of broker quotes										70.00%	92.00%	81.00%
Discount rate														1.00%	12.00%	2.70%	19.00%	1.60%	15.70%									1.10%	0.90%	1.00%	3.20%	3.40%	2.70%	1.60%	2.00%	1.60%			1.40%	5.30%	3.40%
Constant prepayment rate													10.00%	11.00%		19.00%		17.00%											9.00%			18.00%			15.00%				0.00%	24.00%	11.00%