Accounting Policies - Principles of Consolidation (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Variable Interest Entity [Line Items]
Number of Subsidiaries	2
Loans held for investment in consolidated trust, at amortized cost	$ 609,464,000			$ 629,989,000
Debt securities of consolidated trusts held by third parties	312,643,000			261,760,000
Guarantee and commitment fees	6,518,000		6,612,000
On-balance sheet [Member]
Variable Interest Entity [Line Items]
Loans held for investment in consolidated trust, at amortized cost	609,464,000	[1]		629,989,000	[2]
Debt securities of consolidated trusts held by third parties	312,643,000	[3]		261,760,000	[4]
Farm & Ranch [Member]
Variable Interest Entity [Line Items]
Other Liabilities	100,000			2,300,000
Guarantee and commitment fees	3,909,000		3,671,000
Farm & Ranch [Member] | On-balance sheet [Member]
Variable Interest Entity [Line Items]
Loans held for investment in consolidated trust, at amortized cost	312,569,000	[1]		259,509,000	[2]
Debt securities of consolidated trusts held by third parties	312,643,000	[3]		261,760,000	[4]
USDA Guarantees [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Unamortized Discount (Premium), Net	700,000			100,000
Guarantee and commitment fees	26,000		33,000
USDA Guarantees [Member] | On-balance sheet [Member]
Variable Interest Entity [Line Items]
Loans held for investment in consolidated trust, at amortized cost	0	[1]		0	[2]
Debt securities of consolidated trusts held by third parties	0	[3]		0	[4]
Rural Utilities [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Unamortized Premium	4,400,000			16,200,000
Guarantee and commitment fees	877,000		948,000
Rural Utilities [Member] | On-balance sheet [Member]
Variable Interest Entity [Line Items]
Loans held for investment in consolidated trust, at amortized cost	296,895,000	[1]		370,480,000
Debt securities of consolidated trusts held by third parties	0	[3]		0
Institutional Credit [Member] [Member]
Variable Interest Entity [Line Items]
Debt Instrument, Unamortized Discount (Premium), Net	3,100,000			3,200,000
Guarantee and commitment fees	2,237,000		2,140,000
Institutional Credit [Member] [Member] | On-balance sheet [Member]
Variable Interest Entity [Line Items]
Loans held for investment in consolidated trust, at amortized cost	0	[1]		0	[2]
Debt securities of consolidated trusts held by third parties	0	[3]		0	[4]
Corporate [Member]
Variable Interest Entity [Line Items]
Guarantee and commitment fees	0		0
Investments [Member] | Corporate [Member] | On-balance sheet [Member]
Variable Interest Entity [Line Items]
Loans held for investment in consolidated trust, at amortized cost	0	[1]		0	[2]
Debt securities of consolidated trusts held by third parties	0	[3]		0	[4]
FMMSC [Member]
Variable Interest Entity [Line Items]
Guarantee and commitment fees	2,600,000		2,600,000
Farmer Mac Guaranteed Securities Trusts [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	54,706,000	[5]		54,482,000	[6]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	50,894,000	[7]		51,088,000	[8]
Farmer Mac Guaranteed Securities Trusts [Member] | Farm & Ranch [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	[5]		0	[6]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	[7]		0	[8]
Farmer Mac Guaranteed Securities Trusts [Member] | Farm & Ranch [Member] | Off-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	731,574,000			765,751,000
Farmer Mac Guaranteed Securities Trusts [Member] | USDA Guarantees [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	21,608,000	[5]		21,234,000	[6]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	20,894,000	[7]		21,088,000	[8]
Farmer Mac Guaranteed Securities Trusts [Member] | USDA Guarantees [Member] | Off-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	19,562,000	[7],[9]		20,222,000	[8],[9]
Farmer Mac Guaranteed Securities Trusts [Member] | Rural Utilities [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0			0	[6]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0			0	[8]
Farmer Mac Guaranteed Securities Trusts [Member] | Rural Utilities [Member] | Off-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	[7],[9]		0
Farmer Mac Guaranteed Securities Trusts [Member] | Institutional Credit [Member] [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	33,098,000	[5]		33,248,000	[6]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	30,000,000	[7]		30,000,000	[8]
Farmer Mac Guaranteed Securities Trusts [Member] | Institutional Credit [Member] [Member] | Off-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	970,000,000	[7],[9]		970,000,000	[8],[9]
Farmer Mac Guaranteed Securities Trusts [Member] | Investments [Member] | Corporate [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0			0	[6]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	[7]		0	[8]
Investment Securities Trusts [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	572,345,000	[10]		533,688,000	[8]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	579,225,000	[10],[7]		540,726,000	[11],[8]
Investment Securities Trusts [Member] | Off-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	1,721,136,000	[7],[9]		1,755,973,000	[8],[9]
Investment Securities Trusts [Member] | Farm & Ranch [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	[10]		0	[8]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	[10],[7]		0	[11],[8]
Investment Securities Trusts [Member] | USDA Guarantees [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	[10]		0	[8]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	[10],[7]		0	[11],[8]
Investment Securities Trusts [Member] | Rural Utilities [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0			0	[8]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	[10],[7]		0	[11],[8]
Investment Securities Trusts [Member] | Institutional Credit [Member] [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	0	[10]		0	[8]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	0	[10],[7]		0	[11],[8]
Investment Securities Trusts [Member] | Investments [Member] | Corporate [Member] | On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net	572,345,000			533,688,000
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	579,225,000			540,726,000	[11],[8]
Investment Securities Trusts [Member] | Investments [Member] | Corporate [Member] | Off-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	$ 0	[7],[9]		$ 0	[8],[9]

[1] (1) Includes unamortized premiums related to Rural Utilities of $4.4 million.

[2] (1) Includes unamortized premiums related to Rural Utilities of $16.2 million.

[3] (2) Includes borrower remittances of $0.1 million, which have not been passed through to third party investors as of March 31, 2014.

[4] (2) Includes borrower remittances of $2.3 million, which have not been passed through to third party investors as of December 31, 2013.

[5] (3) Includes unamortized premiums and discounts and fair value adjustments related to USDA Guarantees and Institutional Credit of $0.7 million and $3.1 million, respectively.

[6] (3) Includes unamortized premiums and discounts and fair value adjustments related to USDA Guarantees and Institutional Credit of $0.1 million and $3.2 million, respectively.

[7] (4) Farmer Mac uses unpaid principal balance and outstanding face amount of investment securities to represent maximum exposure to loss.

[8] (4) Farmer Mac uses unpaid principal balance and the outstanding face amount of investment securities to represent maximum exposure to loss.

[9] (6) The Farm & Ranch amount relates to unconsolidated trusts where Farmer Mac determined it was not the primary beneficiary due to shared power with an unrelated party.

[10] (5) Includes auction-rate certificates, asset-backed securities and government-sponsored enterprise ("GSE")-guaranteed mortgage-backed securities.

[11] (5) Includes auction-rate certificates, asset-backed securities and GSE-guaranteed mortgage-backed securities.