Business Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Segment Reporting Information [Line Items]
Interest income	$ 71,578	[1]	$ 66,852	[1]	$ 144,709	[1]	$ 130,924	[1]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Interest expense	(36,961)	[2]	(37,640)	[2]	(75,884)	[2]	(74,693)	[2]
Net interest income	34,617		29,212		68,825		56,231
Guarantee and commitment fees	6,064		6,320		11,994		12,707
Other income/(expense)	(33,345)	[3]	(14,205)	[3]	(25,097)	[3]	(5,545)	[3]
Non-interest (loss)/income	(27,281)		(7,885)		(13,103)		7,162
(Provision for)/release of loan losses	1,220		(160)		800		(1,441)
Release of (provision for) losses	(1,394)		935		(1,424)		2,869
Other non-interest expense	(7,815)		(8,126)		(15,627)		(16,738)
Non-interest expense	(9,209)	[4]	(7,191)	[4]	(17,051)	[4]	(13,869)	[4]
(Loss)/income before income taxes	(653)		13,976		39,471		48,083
Income tax (benefit)/expense	2,629		(2,539)		(9,025)		(12,056)
Net income	1,976		11,437		30,446		36,027
Preferred stock dividends	(720)		(720)		(1,440)		(1,440)
Non-controlling interest - preferred stock dividends	(5,547)		(5,547)		(11,094)		(11,094)
Net (loss)/income attributable to common stockholders	(4,291)		5,170		17,912		23,493
Total assets at carrying value	12,050,414		10,444,828		12,050,414		10,444,828		11,883,508
Total on - and off - balance sheet program assets at principal balance	12,250,420		12,198,497		12,250,420		12,198,497
Farmer Mac I
Segment Reporting Information [Line Items]
Interest income	36,897	[1]	34,555	[1]	74,441	[1]	66,634	[1]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	(543)		(839)		(1,273)		(1,713)
Interest expense	(19,605)	[2]	(22,398)	[2]	(41,545)	[2]	(42,676)	[2]
Net interest income	16,749		11,318		31,623		22,245
Guarantee and commitment fees	5,466		5,824		10,789		11,589
Other income/(expense)	514	[3]	1,261	[3]	951	[3]	2,223	[3]
Non-interest (loss)/income	5,980		7,085		11,740		13,812
(Provision for)/release of loan losses	1,220		(160)		800		(1,441)
Release of (provision for) losses	(1,394)		935		(1,424)		2,869
Other non-interest expense	(3,576)		(3,992)		(7,068)		(8,760)
Non-interest expense	(4,970)	[4]	(3,057)	[4]	(8,492)	[4]	(5,891)	[4]
(Loss)/income before income taxes	18,979		15,186		35,671		28,725
Income tax (benefit)/expense	(6,643)		(5,315)		(12,485)		(10,054)
Net income	12,336		9,871		23,186		18,671
Preferred stock dividends	0		0		0		0
Non-controlling interest - preferred stock dividends	0		0		0		0
Net (loss)/income attributable to common stockholders	12,336		9,871		23,186		18,671
Total assets at carrying value	4,842,598		3,743,934		4,842,598		3,743,934
Total on - and off - balance sheet program assets at principal balance	8,513,212		8,498,421		8,513,212		8,498,421
Farmer Mac II [Member]
Segment Reporting Information [Line Items]
Interest income	14,197	[1]	14,045	[1]	28,512	[1]	27,710	[1]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Interest expense	(11,407)	[2]	(11,321)	[2]	(22,956)	[2]	(22,319)	[2]
Net interest income	2,790		2,724		5,556		5,391
Guarantee and commitment fees	41		50		88		103
Other income/(expense)	172	[3]	59	[3]	274	[3]	105	[3]
Non-interest (loss)/income	213		109		362		208
(Provision for)/release of loan losses	0		0		0		0
Release of (provision for) losses	0		0		0		0
Other non-interest expense	(744)		(712)		(1,508)		(1,375)
Non-interest expense	(744)	[4]	(712)	[4]	(1,508)	[4]	(1,375)	[4]
(Loss)/income before income taxes	2,259		2,121		4,410		4,224
Income tax (benefit)/expense	(791)		(742)		(1,544)		(1,478)
Net income	1,468		1,379		2,866		2,746
Preferred stock dividends	0		0		0		0
Non-controlling interest - preferred stock dividends	0		0		0		0
Net (loss)/income attributable to common stockholders	1,468		1,379		2,866		2,746
Total assets at carrying value	1,612,384		1,422,554		1,612,384		1,422,554
Total on - and off - balance sheet program assets at principal balance	1,579,187		1,425,883		1,579,187		1,425,883
Rural Utilities
Segment Reporting Information [Line Items]
Interest income	16,124	[1]	13,131	[1]	32,822	[1]	26,793	[1]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Interest expense	(13,118)	[2]	(10,044)	[2]	(26,639)	[2]	(20,704)	[2]
Net interest income	3,006		3,087		6,183		6,089
Guarantee and commitment fees	1,100		1,285		2,390		2,728
Other income/(expense)	0	[3]	0	[3]	1	[3]	0	[3]
Non-interest (loss)/income	1,100		1,285		2,391		2,728
(Provision for)/release of loan losses	0		0		0		0
Release of (provision for) losses	0		0		0		0
Other non-interest expense	(1,385)		(1,247)		(2,767)		(2,379)
Non-interest expense	(1,385)	[4]	(1,247)	[4]	(2,767)	[4]	(2,379)	[4]
(Loss)/income before income taxes	2,721		3,125		5,807		6,438
Income tax (benefit)/expense	(952)		(1,094)		(2,032)		(2,254)
Net income	1,769		2,031		3,775		4,184
Preferred stock dividends	0		0		0		0
Non-controlling interest - preferred stock dividends	0		0		0		0
Net (loss)/income attributable to common stockholders	1,769		2,031		3,775		4,184
Total assets at carrying value	2,226,318		2,353,748		2,226,318		2,353,748
Total on - and off - balance sheet program assets at principal balance	2,158,021		2,274,193		2,158,021		2,274,193
Corporate
Segment Reporting Information [Line Items]
Interest income	6,024	[1]	7,033	[1]	12,256	[1]	14,220	[1]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	0		0		0		0
Interest expense	(1,361)	[2]	(3,174)	[2]	(2,777)	[2]	(7,314)	[2]
Net interest income	4,663		3,859		9,479		6,906
Guarantee and commitment fees	0		0		0		0
Other income/(expense)	(717)	[3]	(646)	[3]	(1,240)	[3]	(740)	[3]
Non-interest (loss)/income	(717)		(646)		(1,240)		(740)
(Provision for)/release of loan losses	0		0		0		0
Release of (provision for) losses	0		0		0		0
Other non-interest expense	(2,110)		(2,175)		(4,284)		(4,224)
Non-interest expense	(2,110)	[4]	(2,175)	[4]	(4,284)	[4]	(4,224)	[4]
(Loss)/income before income taxes	1,836		1,038		3,955		1,942
Income tax (benefit)/expense	1,759		1,989		3,406		4,094
Net income	3,595		3,027		7,361		6,036
Preferred stock dividends	(720)		(720)		(1,440)		(1,440)
Non-controlling interest - preferred stock dividends	(5,547)		(5,547)		(11,094)		(11,094)
Net (loss)/income attributable to common stockholders	(2,672)		(3,240)		(5,173)		(6,498)
Total assets at carrying value	3,369,114		2,924,592		3,369,114		2,924,592
Total on - and off - balance sheet program assets at principal balance	0		0		0		0
Reconciling Adjustments
Segment Reporting Information [Line Items]
Interest income	(1,664)	[1]	(1,912)	[1]	(3,322)	[1]	(4,433)	[1]
Interest income related to consolidated trusts owned by third parties reclassified to guarantee fee income	543		839		1,273		1,713
Interest expense	8,530	[2]	9,297	[2]	18,033	[2]	18,320	[2]
Net interest income	7,409		8,224		15,984		15,600
Guarantee and commitment fees	(543)		(839)		(1,273)		(1,713)
Other income/(expense)	(33,314)	[3]	(14,879)	[3]	(25,083)	[3]	(7,133)	[3]
Non-interest (loss)/income	(33,857)		(15,718)		(26,356)		(8,846)
(Provision for)/release of loan losses	0		0		0		0
Release of (provision for) losses	0		0		0		0
Other non-interest expense	0		0		0		0
Non-interest expense	0	[4]	0	[4]	0	[4]	0	[4]
(Loss)/income before income taxes	(26,448)	[5]	(7,494)	[5]	(10,372)	[5]	6,754	[5]
Income tax (benefit)/expense	9,256		2,623		3,630		(2,364)
Net income	(17,192)	[5]	(4,871)	[5]	(6,742)	[5]	4,390	[5]
Preferred stock dividends	0		0		0		0
Non-controlling interest - preferred stock dividends	0		0		0		0
Net (loss)/income attributable to common stockholders	(17,192)	[5]	(4,871)	[5]	(6,742)	[5]	4,390	[5]
Total assets at carrying value	0		0		0		0
Total on - and off - balance sheet program assets at principal balance	$ 0		$ 0		$ 0		$ 0

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

[2] Based on effective funding cost determined for each operating segment, including expenses related to interest rate swaps, which are included in Losses on financial derivatives on the GAAP financial statements.

[3] Includes reconciling adjustments for the reclassification of yield maintenance income and 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 II Guaranteed Securities and USDA Guaranteed Securities.(4)Includes directl

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

[5] 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: (loss)/income before income taxes, net income, and net (loss)/income attributable to common stockholders, respectively.