Business Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Segment Reporting Information [Line Items]
Total interest income	$ 61,745	[1]	$ 71,578	[2]	$ 123,243	[1]	$ 144,709	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Interest Expense	(33,584)	[3]	(36,961)	[4]	(66,712)	[3]	(75,884)	[4]
Net interest income	28,161		34,617		56,531		68,825
Guaranty Fee Income	6,759		6,064		13,371		11,994
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	19,724	[5]	(33,345)	[6]	25,557	[5]	(25,097)	[6]
Noninterest Income	26,483		(27,281)		38,928		(13,103)
Provision for loan losses	529		1,220		99		800
Income/(loss) before income taxes	47,209		(653)		78,513		39,471
Income tax (benefit)/expense	(13,036)		2,629		(21,752)		(9,025)
Net income	34,173		1,976		56,761		30,446
Preferred stock dividends	(881)		(720)		(1,732)		(1,440)
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	(5,547)		(5,547)		(11,094)		(11,094)
Net income attributable to common stockholders	27,745		(4,291)		43,935		17,912
Total assets at carrying value	12,935,951		12,050,414		12,935,951		12,050,414		12,622,201
On and Off Balance Sheet Program Assets, At Principal Balance	13,595,518		12,250,420		13,595,518		12,250,420
Provision for Other Credit Losses	175		(1,394)		(571)		(1,424)
Noninterest Expense, Excluding Loan, Lease and Other Losses	8,139		(7,815)		16,474		(15,627)
Noninterest Expense	(7,964)	[7]	(9,209)	[7]	(17,045)	[7]	(17,051)	[7]
Farm & Ranch [Member]
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	29,365	[1]	36,897	[2]	58,179	[1]	74,441	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	(195)		(543)		(375)		(1,273)
Segment interest expense	(12,845)	[3]	(19,605)	[4]	(25,430)	[3]	(41,545)	[4]
Segment net effective spread	16,325		16,749		32,374		31,623
Segment guarantee fee income	5,860		5,466		11,660		10,789
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	1,299	[5]	514	[6]	1,894	[5]	951	[6]
Segment non interest income	7,159		5,980		13,554		11,740
Provision for loan losses	529		1,220		99		800
Segment core earnings before income taxes	20,189		18,979		37,485		35,671
Income tax (benefit)/expense	(7,067)		(6,643)		(13,120)		(12,485)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	13,122		12,336		24,365		23,186
Preferred stock dividends	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0		0		0
Segment core earnings	13,122		12,336		24,365		23,186
Total assets at carrying value	5,468,909		4,842,598		5,468,909		4,842,598
On and Off Balance Sheet Program Assets, At Principal Balance	9,325,489		8,513,212		9,325,489		8,513,212
Provision for Other Credit Losses	175		(1,394)		(571)		(1,424)
Noninterest Expense, Excluding Loan, Lease and Other Losses	(3,999)		(3,576)		(7,971)		(7,068)
Noninterest Expense	(3,824)	[7]	(4,970)	[7]	(8,542)	[7]	(8,492)	[7]
USDA Guarantees [Member]
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	13,157	[1]	14,197	[2]	26,498	[1]	28,512	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Segment interest expense	(10,419)	[3]	(11,407)	[4]	(20,827)	[3]	(22,956)	[4]
Segment net effective spread	2,738		2,790		5,671		5,556
Segment guarantee fee income	42		41		75		88
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	317	[5]	172	[6]	517	[5]	274	[6]
Segment non interest income	359		213		592		362
Provision for loan losses	0		0		0		0
Segment core earnings before income taxes	2,339		2,259		4,691		4,410
Income tax (benefit)/expense	(819)		(791)		(1,642)		(1,544)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	1,520		1,468		3,049		2,866
Preferred stock dividends	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0		0		0
Segment core earnings	1,520		1,468		3,049		2,866
Total assets at carrying value	1,659,134		1,612,384		1,659,134		1,612,384
On and Off Balance Sheet Program Assets, At Principal Balance	1,667,170		1,579,187		1,667,170		1,579,187
Provision for Other Credit Losses	0		0		0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	(758)		(744)		(1,572)		(1,508)
Noninterest Expense	(758)	[7]	(744)	[7]	(1,572)	[7]	(1,508)	[7]
Rural Utilities [Member]
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	14,991	[1]	16,124	[2]	29,880	[1]	32,822	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Segment interest expense	(11,958)	[3]	(13,118)	[4]	(23,833)	[3]	(26,639)	[4]
Segment net effective spread	3,033		3,006		6,047		6,183
Segment guarantee fee income	1,052		1,100		2,011		2,390
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	0	[5]	0	[6]	0	[5]	1	[6]
Segment non interest income	1,052		1,100		2,011		2,391
Provision for loan losses	0		0		0		0
Segment core earnings before income taxes	2,750		2,721		5,310		5,807
Income tax (benefit)/expense	(963)		(952)		(1,859)		(2,032)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	1,787		1,769		3,451		3,775
Preferred stock dividends	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0		0		0
Segment core earnings	1,787		1,769		3,451		3,775
Total assets at carrying value	2,631,931		2,226,318		2,631,931		2,226,318
On and Off Balance Sheet Program Assets, At Principal Balance	2,602,859		2,158,021		2,602,859		2,158,021
Provision for Other Credit Losses	0		0		0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	(1,335)		(1,385)		(2,748)		(2,767)
Noninterest Expense	(1,335)	[7]	(1,385)	[7]	(2,748)	[7]	(2,767)	[7]
Corporate
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	5,471	[1]	6,024	[2]	11,205	[1]	12,256	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Segment interest expense	(1,504)	[3]	(1,361)	[4]	(2,971)	[3]	(2,777)	[4]
Segment net effective spread	3,967		4,663		8,234		9,479
Segment guarantee fee income	0		0		0		0
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	2,782	[5]	(717)	[6]	2,220	[5]	(1,240)	[6]
Segment non interest income	2,782		(717)		2,220		(1,240)
Provision for loan losses	0		0		0		0
Segment core earnings before income taxes	4,702		1,836		6,271		3,955
Income tax (benefit)/expense	1,842		1,759		3,533		3,406
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	6,544		3,595		9,804		7,361
Preferred stock dividends	(881)		(720)		(1,732)		(1,440)
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	(5,547)		(5,547)		(11,094)		(11,094)
Segment core earnings	116		(2,672)		(3,022)		(5,173)
Total assets at carrying value	3,175,977		3,369,114		3,175,977		3,369,114
On and Off Balance Sheet Program Assets, At Principal Balance	0		0		0		0
Provision for Other Credit Losses	0		0		0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	(2,047)		(2,110)		(4,183)		(4,284)
Noninterest Expense	(2,047)	[7]	(2,110)	[7]	(4,183)	[7]	(4,284)	[7]
Reconciling Adjustments
Segment Reporting Information [Line Items]
Segment interest and dividend income operating	(1,239)	[1]	(1,664)	[2]	(2,519)	[1]	(3,322)	[2]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	195		543		375		1,273
Segment interest expense	3,142	[3]	8,530	[4]	6,349	[3]	18,033	[4]
Segment net effective spread	2,098		7,409		4,205		15,984
Segment guarantee fee income	(195)		(543)		(375)		(1,273)
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	15,326	[5]	(33,314)	[6]	20,926	[5]	(25,083)	[6]
Segment non interest income	15,131		(33,857)		20,551		(26,356)
Provision for loan losses	0		0		0		0
Segment core earnings before income taxes	17,229	[8]	(26,448)	[8]	24,756	[8]	(10,372)	[8]
Income tax (benefit)/expense	(6,029)		9,256		(8,664)		3,630
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	11,200	[8]	(17,192)	[8]	16,092	[8]	(6,742)	[8]
Preferred stock dividends	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest - preferred stock dividends	0		0		0		0
Segment core earnings	11,200	[8]	(17,192)	[8]	16,092	[8]	(6,742)	[8]
Total assets at carrying value	0		0		0		0
On and Off Balance Sheet Program Assets, At Principal Balance	0		0		0		0
Provision for Other Credit Losses	0		0		0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	0		0		0		0
Noninterest Expense	$ 0	[7]	$ 0	[7]	$ 0	[7]	$ 0	[7]

[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/(losses) on financial derivatives and hedging activities" on the consolidated 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/(losses) on financial derivatives and hedging activities" on the consolidated 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 income measures: income before income taxes, net income, and net income attributable to common stockholders, respectively.