Business Segment Reporting - (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Segment Reporting Information, Profit (Loss) [Abstract]
Interest and Dividend Income, Operating	$ 60,882	[1]	$ 62,975	[2]	$ 172,375	[1]	$ 186,218	[2]
Interest Income Reclassification	0		0		0		0
Total interest expense	48,886	[3]	34,787	[4]	126,114	[3]	101,499	[4]
Net effective spread	11,996		28,188		46,261		84,719
Guarantee and commitment fees	6,172		6,819		19,093		20,190
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	17,283	[5]	3,002	[6]	13,025	[5]	28,559	[6]
Noninterest Income	23,455		9,821		32,118		48,749
Provision for Loan Losses Expensed	511		(499)		(499)		(598)
(Release of)/provision for reserve for losses	(1,315)		463		(2,188)		1,034
Noninterest Expense, Excluding Loan, Lease and Other Losses	8,410		7,978		25,086		24,452
Noninterest Expense	7,095	[7]	8,441	[7]	22,898	[7]	25,486	[7]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	27,845		30,067		55,980		108,580
Income tax expense	7,564		8,226		55		29,978
Net income	20,281		21,841		55,925		78,602
Preferred Stock Dividends, Income Statement Impact	3,283		881		6,543		2,613
Net Income (Loss) Attributable to Noncontrolling Interest	5,412		5,547		16,778		16,641
Net Income (Loss) Available to Common Stockholders, Basic	11,586		15,413		32,604		59,348
Segment Reporting Information, Additional Information [Abstract]
Assets	14,525,697		13,085,007		14,525,697		13,085,007		13,361,780
On and Off Balance Sheet Program Assets, At Principal Balance	14,004,822		13,786,266		14,004,822		13,786,266
Farm & Ranch [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Interest and Dividend Income, Operating	20,052	[1]	16,398	[2]	57,988	[1]	47,860	[2]
Interest Income Reclassification	(508)		(227)		(1,552)		(602)
Total interest expense	11,337	[3]	8,191	[4]	33,295	[3]	22,967	[4]
Net effective spread	8,207		7,980		23,141		24,291
Guarantee and commitment fees	3,716		3,725		11,432		11,099
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	369	[5]	157	[6]	742	[5]	2,051	[6]
Noninterest Income	4,085		3,882		12,174		13,150
Provision for Loan Losses Expensed	511		(499)		(499)		(598)
(Release of)/provision for reserve for losses	(1,315)		463		(2,188)		1,034
Noninterest Expense, Excluding Loan, Lease and Other Losses	3,797		3,600		11,263		11,199
Noninterest Expense	2,482	[7]	4,063	[7]	9,075	[7]	12,233	[7]
Segment core earnings before income taxes	9,299		8,298		26,739		25,806
Income tax expense	3,255		2,904		9,358		9,032
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	6,044		5,394		17,381		16,774
Preferred Stock Dividends, Income Statement Impact	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest	0		0		0		0
Segment core earnings	6,044		5,394		17,381		16,774
Segment Reporting Information, Additional Information [Abstract]
Assets	2,428,603		2,003,547		2,428,603		2,003,547
On and Off Balance Sheet Program Assets, At Principal Balance	5,314,437		5,035,748		5,314,437		5,035,748
USDA Guarantees [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Interest and Dividend Income, Operating	14,183	[1]	13,461	[2]	40,449	[1]	39,959	[2]
Interest Income Reclassification	0				0		0
Total interest expense	9,110	[3]	8,956	[4]	27,433	[3]	26,252	[4]
Net effective spread	5,073		4,505		13,016		13,707
Guarantee and commitment fees	49		30		98		105
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	13	[5]	241	[6]	49	[5]	758	[6]
Noninterest Income	62		271		147		863
Provision for Loan Losses Expensed	0		0		0		0
(Release of)/provision for reserve for losses	0				0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	747		711		2,242		2,168
Noninterest Expense	747	[7]	711	[7]	2,242	[7]	2,168	[7]
Segment core earnings before income taxes	4,388		4,065		10,921		12,402
Income tax expense	1,535		1,423		3,823		4,341
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	2,853		2,642		7,098		8,061
Preferred Stock Dividends, Income Statement Impact	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest	0		0		0		0
Segment core earnings	2,853		2,642		7,098		8,061
Segment Reporting Information, Additional Information [Abstract]
Assets	1,772,333		1,674,309		1,772,333		1,674,309
On and Off Balance Sheet Program Assets, At Principal Balance	1,759,948		1,676,793		1,759,948		1,676,793
Rural Utilities [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Interest and Dividend Income, Operating	6,703	[1]	8,933	[2]	21,228	[1]	26,903	[2]
Interest Income Reclassification	0				0		0
Total interest expense	3,813	[3]	5,959	[4]	13,395	[3]	17,690	[4]
Net effective spread	2,890		2,974		7,833		9,213
Guarantee and commitment fees	0		0		0		948
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	9	[5]	0	[6]	9	[5]	0	[6]
Noninterest Income	9		0		9		948
Provision for Loan Losses Expensed	0		0		0		0
(Release of)/provision for reserve for losses	0				0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	762		777		2,369		2,350
Noninterest Expense	762	[7]	777	[7]	2,369	[7]	2,350	[7]
Segment core earnings before income taxes	2,137		2,197		5,473		7,811
Income tax expense	749		769		1,917		2,734
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	1,388		1,428		3,556		5,077
Preferred Stock Dividends, Income Statement Impact	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest	0		0		0		0
Segment core earnings	1,388		1,428		3,556		5,077
Segment Reporting Information, Additional Information [Abstract]
Assets	981,300		1,049,840		981,300		1,049,840
On and Off Balance Sheet Program Assets, At Principal Balance	978,637		1,017,774		978,637		1,017,774
Institutional Credit [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Interest and Dividend Income, Operating	16,223	[1]	19,766	[1],[2]	51,244	[1]	58,393	[1],[2]
Interest Income Reclassification	0				0		0
Total interest expense	8,928	[3]	13,561	[3],[4]	30,020	[3]	40,348	[3],[4]
Net effective spread	7,295		6,205		21,224		18,045
Guarantee and commitment fees	2,915		3,291		9,115		8,640
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	0	[5]	0	[5],[6]	0	[5]	0	[5],[6]
Noninterest Income	2,915		3,291		9,115		8,640
Provision for Loan Losses Expensed	0		0		0		0
(Release of)/provision for reserve for losses	0				0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	478		445		1,415		1,345
Noninterest Expense	478	[7]	445	[7]	1,415	[7]	1,345	[7]
Segment core earnings before income taxes	9,732		9,051		28,924		25,340
Income tax expense	3,407		3,168		10,124		8,869
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	6,325		5,883		18,800		16,471
Preferred Stock Dividends, Income Statement Impact	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest	0		0		0		0
Segment core earnings	6,325		5,883		18,800		16,471
Segment Reporting Information, Additional Information [Abstract]
Assets	5,016,670		5,144,693		5,016,670		5,144,693
On and Off Balance Sheet Program Assets, At Principal Balance	5,951,800		6,055,951		5,951,800		6,055,951
Corporate [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Interest and Dividend Income, Operating	4,683	[1]	5,263	[2]	15,103	[1]	16,468	[2]
Interest Income Reclassification	0				0		0
Total interest expense	910	[3]	1,146	[4]	3,028	[3]	3,617	[4]
Net effective spread	3,773		4,117		12,075		12,851
Guarantee and commitment fees	0		0		0		0
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	(2,392)	[5]	(825)	[6]	(3,566)	[5]	1,395	[6]
Noninterest Income	(2,392)		(825)		(3,566)		1,395
Provision for Loan Losses Expensed	0		0		0		0
(Release of)/provision for reserve for losses	0				0		0
Noninterest Expense, Excluding Loan, Lease and Other Losses	2,626		2,445		7,797		7,390
Noninterest Expense	2,626	[7]	2,445	[7]	7,797	[7]	7,390	[7]
Segment core earnings before income taxes	(1,245)		847		712		6,856
Income tax expense	(2,619)		(2,001)		(19,295)		(5,625)
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	1,374		2,848		20,007		12,481
Preferred Stock Dividends, Income Statement Impact	3,283		881		6,543		2,613
Net Income (Loss) Attributable to Noncontrolling Interest	5,412		5,547		16,778		16,641
Segment core earnings	(7,321)		(3,580)		(3,314)		(6,773)
Segment Reporting Information, Additional Information [Abstract]
Assets	4,326,791		3,212,618		4,326,791		3,212,618
On and Off Balance Sheet Program Assets, At Principal Balance
Segment Reconciling Items [Member]
Segment Reporting Information, Profit (Loss) [Abstract]
Interest and Dividend Income, Operating	(962)	[1]	(846)	[2]	(13,637)	[1]	(3,365)	[2]
Interest Income Reclassification	508		227		1,552		602
Total interest expense	14,788	[3]	(3,026)	[4]	18,943	[3]	(9,375)	[4]
Net effective spread	(15,242)		2,407		(31,028)		6,612
Guarantee and commitment fees	(508)		(227)		(1,552)		(602)
Other Non-Interest Income (Expense), Excluding Guarantee and Commitment Fees	19,284	[5]	3,429	[6]	15,791	[5]	24,355	[6]
Noninterest Income	18,776		3,202		14,239		23,753
Provision for Loan Losses Expensed	0		0		0		0
(Release of)/provision for reserve for 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]
Segment core earnings before income taxes	3,534	[8]	5,609	[8]	(16,789)	[8]	30,365	[8]
Income tax expense	1,237		1,963		(5,872)		10,627
Segment core earnings before preferred stock dividends and attibution of income to non-controlling interest - preferred stock dividends	2,297	[8]	3,646	[8]	(10,917)	[8]	19,738	[8]
Preferred Stock Dividends, Income Statement Impact	0		0		0		0
Net Income (Loss) Attributable to Noncontrolling Interest	0		0		0		0
Segment core earnings	2,297	[8]	3,646	[8]	(10,917)	[8]	19,738	[8]
Segment Reporting Information, Additional Information [Abstract]
Assets	0		0		0		0
On and Off Balance Sheet Program Assets, At Principal Balance	$ 0		$ 0		$ 0		$ 0

[1] Includes reconciling adjustments for the amortization of premiums and discounts on assets consolidated at fair value to reflect core earnings amounts and interest income related to securities purchased under agreements to resell.

[2] Includes reconciling adjustments for the amortization of premiums and discounts 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. Includes reconciling adjustments for interest expense related to securities sold, not yet purchased.

[4] 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.

[5] Includes interest income and interest expense related to securities purchased under agreements to resell and securities sold, not yet purchased, respectively; 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; and a reconciling adjustment related to the recognition of deferred gains over the estimated lives of certain Farmer Mac Guaranteed Securities and USDA Securities.

[6] 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 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.