Accounting Policies - Variable Interest Entities (Details) (USD $)	Dec. 31, 2013		Dec. 31, 2012
Noncontrolling Interest [Line Items]
Loans held for investment in consolidated trusts, at amortized cost	$ 629,989,000		$ 563,575,000
Debt securities of consolidated trusts held by third parties	261,760,000		167,621,000
Debt instrument, unamortized premium	11,500,000		35,100,000
Other liabilities	2,300,000		7,200,000
Farm & Ranch [Member]
Noncontrolling Interest [Line Items]
Debt instrument, unamortized discount (premium), net	3,200,000		1,400,000
Farm & Ranch [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Shared power with unrelated party [Member]
Noncontrolling Interest [Line Items]
Maximum exposure to loss	765,800,000		911,400,000
USDA Guarantees [Member]
Noncontrolling Interest [Line Items]
Debt instrument, unamortized discount (premium), net	100,000		400,000
Rural Utilities [Member]
Noncontrolling Interest [Line Items]
Debt instrument, unamortized premium	16,200,000		34,300,000
On-balance sheet [Member]
Noncontrolling Interest [Line Items]
Loans held for investment in consolidated trusts, at amortized cost	629,989,000	[1]	563,575,000	[2]
Debt securities of consolidated trusts held by third parties	261,760,000	[3]	167,621,000	[4]
On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	54,482,000	[5]	58,051,000	[6]
Maximum exposure to loss	51,088,000	[7]	56,238,000	[8]
On-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Investment Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	533,688,000		724,893,000
Maximum exposure to loss	540,726,000	[7]	737,148,000	[8]
On-balance sheet [Member] | Investments [Member]
Noncontrolling Interest [Line Items]
Loans held for investment in consolidated trusts, at amortized cost	0	[1]	0	[2]
Debt securities of consolidated trusts held by third parties	0	[3]	0	[4]
On-balance sheet [Member] | Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	0	[5]	0	[6]
Maximum exposure to loss	0	[7]	0	[8]
On-balance sheet [Member] | Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Investment Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	533,688,000		724,893,000
Maximum exposure to loss	540,726,000	[7]	737,148,000	[8]
On-balance sheet [Member] | Farm & Ranch [Member]
Noncontrolling Interest [Line Items]
Loans held for investment in consolidated trusts, at amortized cost	259,509,000	[1]	160,436,000	[2]
Debt securities of consolidated trusts held by third parties	261,760,000	[3]	167,621,000	[4]
On-balance sheet [Member] | Farm & Ranch [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	33,248,000	[5]	31,370,000	[6]
Maximum exposure to loss	30,000,000	[7]	30,000,000	[8]
On-balance sheet [Member] | Farm & Ranch [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Investment Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	0		0
Maximum exposure to loss	0	[7]	0	[8]
On-balance sheet [Member] | USDA Guarantees [Member]
Noncontrolling Interest [Line Items]
Loans held for investment in consolidated trusts, at amortized cost	0	[1]	0	[2]
Debt securities of consolidated trusts held by third parties	0	[3]	0	[4]
On-balance sheet [Member] | USDA Guarantees [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	21,234,000	[5]	26,681,000	[6]
Maximum exposure to loss	21,088,000	[7]	26,238,000	[8]
On-balance sheet [Member] | USDA Guarantees [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Investment Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	0		0
Maximum exposure to loss	0	[7]	0	[8]
On-balance sheet [Member] | Rural Utilities [Member]
Noncontrolling Interest [Line Items]
Loans held for investment in consolidated trusts, at amortized cost	370,480,000	[1]	403,139,000	[2]
Debt securities of consolidated trusts held by third parties	0	[3]	0	[4]
On-balance sheet [Member] | Rural Utilities [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	0	[5]	0	[6]
Maximum exposure to loss	0	[7]	0	[8]
On-balance sheet [Member] | Rural Utilities [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Investment Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Carrying value	0		0
Maximum exposure to loss	0	[7]	0	[8]
Off-balance sheet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Investment Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Maximum exposure to loss	1,755,973,000	[7],[9]	1,911,028,000	[10],[8]
Off-balance sheet [Member] | Investments [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Investment Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Maximum exposure to loss	0	[7],[9]	0	[10],[8]
Off-balance sheet [Member] | Farm & Ranch [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Maximum exposure to loss	1,735,751,000	[7],[9]	1,881,370,000	[10],[8]
Off-balance sheet [Member] | USDA Guarantees [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Maximum exposure to loss	20,222,000	[7],[9]	29,658,000	[10],[8]
Off-balance sheet [Member] | Rural Utilities [Member] | Variable Interest Entity, Not Primary Beneficiary [Member] | Farmer Mac Guaranteed Securities Trusts [Member]
Noncontrolling Interest [Line Items]
Maximum exposure to loss	$ 0	[7],[9]	$ 0	[10],[8]

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

[2] Includes unamortized premiums related to Rural Utilities of $34.3 million.

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

[4] Includes borrower remittances of $7.2 million, which have not been passed through to third party investors as of December 31, 2012.

[5] Includes unamortized premiums and discounts and fair value adjustments related to Farm & Ranch and USDA Guarantees of $3.2 million and $0.1 million, respectively.

[6] Includes unamortized premiums and discounts and fair value adjustments related to Farm & Ranch and USDA Guarantees of $1.4 million and $0.4 million, respectively.

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

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

[9] Of the Farm & Ranch amount, $765.8 million relates to unconsolidated trusts where Farmer Mac determined it was not the primary beneficiary due to shared power with an unrelated party.

[10] Of the Farm & Ranch amount, $911.4 million relates to unconsolidated trusts where Farmer Mac determined it was not the primary beneficiary due to shared power with an unrelated party.