Fair Value Disclosures - Summary of Carrying Value and Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Financial Derivatives Asset	$ 7,318	$ 19,718
Security Sold, Not yet Purchased	1,673,532	0
Financial derivatives, Liabilities	54,474	64,388
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	384,123	749,313
Securities Purchased Under Agreements to Resell	1,640,184	0
Loans	3,363,595	3,138,932
Financial Derivatives Asset	7,318	19,718
Debt securities of consolidated trusts held by third parties	373,514	257,512
Financial derivatives, Liabilities	78,296	75,708
Fair Value [Member] \| Investment Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	2,316,843	2,484,075
Fair Value [Member] \| Farmer Mac Guaranteed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	16,209	18,470
Fair Value [Member] \| Long-Term Standby Purchase Commitments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	31,621	33,807
Fair Value [Member] \| Farmer Mac Guarantee [Member] \| Farmer Mac Guaranteed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	5,097,604	5,091,600
Fair Value [Member] \| USDA Guarantee [Member] \| USDA Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	1,683,029	1,612,013
Fair Value [Member] \| Due within one year [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	6,264,106	7,353,356
Fair Value [Member] \| Long-term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	5,455,927	4,977,942
Fair Value [Member] \| Farmer Mac Guaranteed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guaranty Fee Liabilities, Fair Value Disclosure	13,180	15,185
Fair Value [Member] \| Long-Term Standby Purchase Commitments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guaranty Fee Liabilities, Fair Value Disclosure	30,676	32,856
Fair Value [Member] \| Securities Sold, Not yet Purchased [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Security Sold, Not yet Purchased	1,673,532	0
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	384,123	749,313
Securities Purchased Under Agreements to Resell	1,640,686	0
Loans	3,334,417	3,193,248
Financial Derivatives Asset	7,318	19,718
Debt securities of consolidated trusts held by third parties	377,518	261,760
Financial derivatives, Liabilities	78,296	75,708
Reported Value Measurement [Member] \| Investment Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	2,316,843	2,484,075
Reported Value Measurement [Member] \| Farmer Mac Guaranteed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	15,440	16,660
Reported Value Measurement [Member] \| Long-Term Standby Purchase Commitments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guarantee and commitment fees receivable	28,038	27,244
Reported Value Measurement [Member] \| Farmer Mac Guarantee [Member] \| Farmer Mac Guaranteed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	5,094,010	5,091,600
Reported Value Measurement [Member] \| USDA Guarantee [Member] \| USDA Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable Securities	1,683,029	1,612,013
Reported Value Measurement [Member] \| Due within one year [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	6,265,018	7,338,781
Reported Value Measurement [Member] \| Long-term Debt [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes Payable, Fair Value Disclosure	5,401,118	5,001,169
Reported Value Measurement [Member] \| Farmer Mac Guaranteed Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guaranty Fee Liabilities, Fair Value Disclosure	12,411	13,374
Reported Value Measurement [Member] \| Long-Term Standby Purchase Commitments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Guaranty Fee Liabilities, Fair Value Disclosure	27,092	26,293
Reported Value Measurement [Member] \| Securities Sold, Not yet Purchased [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Security Sold, Not yet Purchased	$ 1,673,532	$ 0

Guaranty Fee Assets, Fair Value Disclosure

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- Definition

Guaranty Fee Liabilities, Fair Value Disclosure

+ References

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- Definition

Marketable Securities, Fair Value Disclosure

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No definition available.

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- Definition

Variable Interest Entity, Consolidated, Fair Value Disclosure, Liabilities

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226008-175313

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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

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Period Type:	duration

- Definition

Fair value portion of federal funds sold and securities borrowed or purchased under agreements to resell.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.13(3)(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Glossary Loan

-URI http://asc.fasb.org/extlink&oid=6517073

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- Definition

Fair value portion of notes payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19,20,22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Fair value of financial instruments sold short by a broker-dealer for their own account (proprietary securities) for trading or investment purposes determined by management based upon quoted prices of a financial instrument with similar characteristics or on a valuation technique or model.

+ References

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