Business Segment Reporting (Details) (USD $)	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Segment Reporting Information [Line Items]
Total interest income	$ 61,498,000	[1]	$ 73,131,000	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0
Total interest expense	(33,128,000)	[3]	(38,923,000)	[4]
Net interest income	28,370,000		34,208,000
Guarantee and commitment fees	6,612,000		5,930,000
Other income/(expense)	5,833,000	[5]	8,248,000	[6]
Non-interest income/(loss)	12,445,000		14,178,000
Provision for loan losses	(430,000)		(420,000)
Release of (provision for) losses	(746,000)		(30,000)
Other non-interest expense	(8,335,000)		(7,812,000)
Non-interest expense	(9,081,000)	[7]	(7,842,000)	[7]
Income/(loss) before income taxes	31,304,000		40,124,000
Income tax (benefit)/expense	(8,716,000)		(11,654,000)
Net income	22,588,000		28,470,000
Preferred stock dividends	(851,000)		(720,000)
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	(5,547,000)		(5,547,000)
Net income attributable to common stockholders	16,190,000		22,203,000
Total assets at carrying value	12,892,672,000		12,311,411,000		12,622,201,000
On and Off Balance Sheet Program Assets, At Principal Balance	13,437,862,000		12,066,425,000
Farm & Ranch [Member]
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	28,814,000	[1]	40,746,000	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	(180,000)		(730,000)
Segment interest expense	(12,585,000)	[3]	(25,142,000)	[4]
Segment net effective spread	16,049,000		14,874,000
Segment guarantee fee income	5,800,000		5,323,000
Other income/(expense)	595,000	[5]	437,000	[6]
Segment non interest income	6,395,000		5,760,000
Provision for loan losses	(430,000)		(420,000)
Release of (provision for) losses	(746,000)		(30,000)
Other non-interest expense	(3,972,000)		(3,492,000)
Non-interest expense	(4,718,000)	[7]	(3,522,000)	[7]
Segment core earnings before income taxes	17,296,000		16,692,000
Income tax (benefit)/expense	(6,053,000)		(5,842,000)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	11,243,000		10,850,000
Preferred stock dividends	0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0
Segment core earnings	11,243,000		10,850,000
Total assets at carrying value	5,309,083,000		5,019,070,000
On and Off Balance Sheet Program Assets, At Principal Balance	9,191,809,000		8,283,483,000
USDA Guarantees [Member]
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	13,341,000	[1]	14,315,000	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0
Segment interest expense	(10,408,000)	[3]	(11,549,000)	[4]
Segment net effective spread	2,933,000		2,766,000
Segment guarantee fee income	33,000		47,000
Other income/(expense)	200,000	[5]	102,000	[6]
Segment non interest income	233,000		149,000
Provision for loan losses	0		0
Release of (provision for) losses	0		0
Other non-interest expense	(814,000)		(764,000)
Non-interest expense	(814,000)	[7]	(764,000)	[7]
Segment core earnings before income taxes	2,352,000		2,151,000
Income tax (benefit)/expense	(823,000)		(753,000)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	1,529,000		1,398,000
Preferred stock dividends	0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0
Segment core earnings	1,529,000		1,398,000
Total assets at carrying value	1,701,413,000		1,567,693,000
On and Off Balance Sheet Program Assets, At Principal Balance	1,648,105,000		1,529,642,000
Rural Utilities [Member]
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	14,889,000	[1]	13,496,000	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0
Segment interest expense	(11,875,000)	[3]	(10,319,000)	[4]
Segment net effective spread	3,014,000		3,177,000
Segment guarantee fee income	959,000		1,290,000
Other income/(expense)	0	[5]	1,000	[6]
Segment non interest income	959,000		1,291,000
Provision for loan losses	0		0
Release of (provision for) losses	0		0
Other non-interest expense	(1,413,000)		(1,382,000)
Non-interest expense	(1,413,000)	[7]	(1,382,000)	[7]
Segment core earnings before income taxes	2,560,000		3,086,000
Income tax (benefit)/expense	(896,000)		(1,080,000)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	1,664,000		2,006,000
Preferred stock dividends	0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0
Segment core earnings	1,664,000		2,006,000
Total assets at carrying value	2,620,213,000		2,314,162,000
On and Off Balance Sheet Program Assets, At Principal Balance	2,597,948,000		2,253,300,000
Corporate
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	5,734,000	[1]	6,232,000	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0
Segment interest expense	(1,467,000)	[3]	(1,416,000)	[4]
Segment net effective spread	4,267,000		4,816,000
Segment guarantee fee income	0		0
Other income/(expense)	(562,000)	[5]	(523,000)	[6]
Segment non interest income	(562,000)		(523,000)
Provision for loan losses	0		0
Release of (provision for) losses	0		0
Other non-interest expense	(2,136,000)		(2,174,000)
Non-interest expense	(2,136,000)	[7]	(2,174,000)	[7]
Segment core earnings before income taxes	1,569,000		2,119,000
Income tax (benefit)/expense	1,691,000		1,647,000
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	3,260,000		3,766,000
Preferred stock dividends	(851,000)		(720,000)
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	(5,547,000)		(5,547,000)
Segment core earnings	(3,138,000)		(2,501,000)
Total assets at carrying value	3,261,963,000		3,410,486,000
On and Off Balance Sheet Program Assets, At Principal Balance	0		0
Reconciling Adjustments
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	(1,280,000)	[1]	(1,658,000)	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	180,000		730,000
Segment interest expense	3,207,000	[3]	9,503,000	[4]
Segment net effective spread	2,107,000		8,575,000
Segment guarantee fee income	(180,000)		(730,000)
Other income/(expense)	5,600,000	[5]	8,231,000	[6]
Segment non interest income	5,420,000		7,501,000
Provision for loan losses	0		0
Release of (provision for) losses	0		0
Other non-interest expense	0		0
Non-interest expense	0	[7]	0	[7]
Segment core earnings before income taxes	7,527,000	[8]	16,076,000	[8]
Income tax (benefit)/expense	(2,635,000)		(5,626,000)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	4,892,000	[8]	10,450,000	[8]
Preferred stock dividends	0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0
Segment core earnings	4,892,000	[8]	10,450,000	[8]
Total assets at carrying value	0		0
On and Off Balance Sheet Program Assets, At Principal Balance	$ 0		$ 0

[1] Includes reconciling adjustments for the amortization of premiums and discounts on assets consolidated at fair value to reflect core earnings amounts.

[2] Includes reconciling adjustments for yield maintenance income and amortization of premiums on assets consolidated at fair value to reflect core earnings amounts.

[3] Based on effective funding cost determined for each operating segment, including expenses related to interest rate swaps not designated as hedges, which are included in "Gains on financial derivatives and hedging activities" on the GAAP financial statements.

[4] Based on effective funding cost determined for each operating segment, including expenses related to interest rate swaps, which are included in "Gains on financial derivatives and hedging activities" on the GAAP financial statements.

[5] Includes reconciling adjustments for the reclassification of expenses related to interest rate swaps not designated as hedges and fair value adjustments on financial derivatives and trading assets. Also includes a reconciling adjustment related to the recognition of deferred gains over the estimated lives of certain Farmer Mac Guaranteed Securities and USDA Guaranteed Securities.

[6] Includes reconciling adjustments for the reclassification of yield maintenance income, expenses related to interest rate swaps and fair value adjustments on financial derivatives and trading assets. Also includes a reconciling adjustment related to the recognition of deferred gains over the estimated lives of certain Farmer Mac Guaranteed Securities and USDA Guaranteed Securities.

[7] Includes directly attributable costs and an allocation of indirectly attributable costs based on headcount.

[8] Net adjustments to reconcile core earnings before income taxes; core earnings before preferred stock dividends and attribution of income to non-controlling interest - preferred stock dividends; and segment core earnings to corresponding GAAP measures: income before income taxes, net income, and net income attributable to common stockholders, respectively.