Farmer Mac Guaranteed Securities and USDA Guaranteed Securities - Farmer Mac Guaranteed Securities and USDA Securities (Details) (USD $) In Thousands, unless otherwise specified	0 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Farmer Mac Guaranteed Securities and USDA Securities [Member]
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance	$ 5,027,885	$ 6,678,377
Available-for-sale Securities, Amortized Cost Basis	5,031,616	6,682,569
Available-for-Sale Gross Unrealized Gains	41,550	67,473
Available-for-Sale Securities Gross Unrealized Losses	28,510	104,773
Available-for-sale, at fair value	5,044,656	6,645,269
Farmer Mac Guaranteed Securities [Member]
Held-to-Maturity Securities [Abstract]
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,652,631
Held-to-maturity Securities, Fair Value	1,656,263
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance	3,343,912	5,087,944
Available-for-sale Securities, Amortized Cost Basis	3,343,471	5,087,551
Available-for-Sale Gross Unrealized Gains	37,224	64,720
Available-for-Sale Securities Gross Unrealized Losses	23,920	60,671
Available-for-sale, at fair value	3,356,775	5,091,600
USDA Securities [Member]
Available-for-sale Securities [Abstract]
Available-for-sale, at fair value	1,687,881	1,553,669
Trading Securities [Abstract]
Trading, at fair value	42,964	58,344
Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities and USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	3,731	4,192
Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	(441)	(393)
Institutional Credit [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	2,600	3,200
Institutional Credit [Member] | Farmer Mac Guaranteed Securities [Member]
Held-to-Maturity Securities [Abstract]
Held-to-Maturity Unpaid Principal Balance	1,640,150
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,652,631
Held to Maturity; Unrealized Holding Gains	4,236
Held to Maturity - Unrealized Holding Loss	604
Held-to-maturity Securities, Fair Value	1,656,263
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance	3,323,463	5,066,855
Available-for-sale Securities, Amortized Cost Basis	3,323,463	5,066,980
Available-for-Sale Gross Unrealized Gains	36,779	64,051
Available-for-Sale Securities Gross Unrealized Losses	23,916	60,665
Available-for-sale, at fair value	3,336,326	5,070,366
Institutional Credit [Member] | Held-to-maturity Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	12,481
Institutional Credit [Member] | Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	0	125
USDA Guarantees [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	0	100
USDA Guarantees [Member] | Farmer Mac Guaranteed Securities [Member]
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance	20,449	21,089
Available-for-sale Securities, Amortized Cost Basis	20,008	20,571
Available-for-Sale Gross Unrealized Gains	445	669
Available-for-Sale Securities Gross Unrealized Losses	4	6
Available-for-sale, at fair value	20,449	21,234
USDA Guarantees [Member] | USDA Securities [Member]
Available-for-sale Securities [Abstract]
Available-for-Sale Securities Unpaid Principal Balance	1,683,973	1,590,433
Available-for-sale Securities, Amortized Cost Basis	1,688,145	1,595,018
Available-for-Sale Gross Unrealized Gains	4,326	2,753
Available-for-Sale Securities Gross Unrealized Losses	4,590	44,102
Available-for-sale, at fair value	1,687,881	1,553,669
Trading Securities [Abstract]
Trading Securities Unpaid Principal Balance	40,833	55,373
Trading Securities Amortized Cost	44,802	60,345
Trading Securities, Unrealized Gains	130	193
Trading Securities, Unrealized Holding Loss	1,968	2,194
Trading, at fair value	42,964	58,344
USDA Guarantees [Member] | Available-for-sale Securities [Member] | Farmer Mac Guaranteed Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	(441)	(518)
USDA Guarantees [Member] | Available-for-sale Securities [Member] | USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	4,172	4,585
USDA Guarantees [Member] | Trading Securities [Member] | USDA Securities [Member]
Schedule of Held-to-Maturity, Available-for-sale, and Trading Securities [Line Items]
Unamortized Premium/(Discount)	$ 3,969	$ 4,972