Quarterly Financial Information (Unaudited) - Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Interest and Dividend Income, Operating	$ 81,241	$ 79,532	$ 77,236	$ 73,891	$ 67,562	$ 66,918	$ 66,392	$ 63,951	$ 311,900		$ 264,823		$ 241,067
Total interest expense	44,528	43,969	42,878	40,251	36,591	34,735	34,528	33,162	171,626		139,016		170,720
Net interest income	36,713	35,563	34,358	33,640	30,971	32,183	31,864	30,789	140,274		125,807		70,347
(Provision for)/release of loan losses	(461)	(191)	(364)	(49)	(3,366)	1,164	(110)	(76)	(1,065)		(2,388)		961
Interest Income (Expense), after Provision for Loan Loss	36,252	35,372	33,994	33,591	27,605	33,347	31,754	30,713	139,209		123,419		71,308
Guarantee and commitment fees	3,789	3,798	3,655	3,626	3,780	3,532	3,388	3,377	14,868	[1]	14,077	[2]	14,694	[3]
Gain (loss) on derivatives instruments and hedging activity net pretax	15,390	(1,601)	(4,696)	(6,782)	1,592	(9,568)	14,389	(3,882)
Gains on trading securities	(474)	1,182	394	358	696	(8)	170	362	1,460		1,220		38,629
(Losses)/gains on sale of available-for-sale investment securities	0	0	0	(9)	0	3	0	6	(9)		9		(238)
Gains/(losses) on sale of real estate owned	0	15	0	0	0		0	(1)	15		(1)		137
Other income	602	707	413	101	372	1,060	260	613	1,823		2,305		1,714
Noninterest Income	19,307	4,101	(234)	(2,706)	6,440	(4,981)	18,207	475	20,468		20,141		33,290
Noninterest Expense	10,977	9,303	10,074	9,966	5,865	10,421	10,853	8,343	40,320	[4]	35,482	[5]	31,492	[6]
Income before income taxes	44,582	30,170	23,686	20,919	28,180	17,945	39,108	22,845	119,357		108,078		73,106
Income tax expense	15,793	10,529	8,400	7,335	9,912	6,327	13,769	4,231	42,057		34,239		2,824
Net income	28,789	19,641	15,286	13,584	18,268	11,618	25,339	18,614	77,300		73,839		70,282
Less: Net loss/(income) attributable to non-controlling interest	(28)	18	16	28	60	36	119	(5,354)	34		(5,139)		(22,192)
Net Income (Loss) Attributable to Parent	28,761	19,659	15,302	13,612	18,328	11,654	25,458	13,260	77,334		68,700		48,090
Preferred Stock Dividends, Income Statement Impact	(3,296)	(3,295)	(3,296)	(3,295)	(3,296)	(3,295)	(3,296)	(3,295)	(13,182)		(13,182)		(9,839)
Net Income (Loss) Available to Common Stockholders, Basic	$ 25,465	$ 16,364	$ 12,006	$ 10,317	$ 15,032	$ 8,359	$ 22,162	$ 1,818	$ 64,152		$ 47,371		$ 38,251
Basic earnings per common share	$ 2.42	$ 1.56	$ 1.15	$ 0.99	$ 1.39	$ 0.76	$ 2.01	$ 0.17	$ 6.12		$ 4.33		$ 3.50
Diluted earnings per common share	$ 2.38	$ 1.54	$ 1.13	$ 0.94	$ 1.35	$ 0.74	$ 1.94	$ 0.16	$ 5.97000		$ 4.19000		$ 3.37000
Loss on retirement of preferred stock					$ 0	$ 0	$ 0	$ (8,147)	$ 0		$ (8,147)		$ 0

[1] Includes the reclassification of interest income and interest expense from consolidated trusts owned by third parties to guarantee and commitment fees, to reflect management's view that the net interest income Farmer Mac earns is effectively a guarantee fee.

[2] Includes the reclassification of interest income and interest expense from consolidated trusts owned by third parties to guarantee and commitment fees, to reflect management's view that the net interest income Farmer Mac earns is effectively a guarantee fee.

[3] Includes the reclassification of interest income and interest expense from consolidated trusts owned by third parties to guarantee and commitment fees, to reflect management's view that the net interest income Farmer Mac earns is effectively a guarantee fee.

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

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

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