Farmer Mac Guaranteed Securities and USDA Guaranteed Securities - Narrative (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale and Trading Securities [Line Items]
Available-for-Sale Continuous Unrealized Loss Position more than 12 months, Aggregate Losses	$ 15,777	$ 15,430
Farmer Mac Guaranteed Securities [Member] | Farmer Mac Guarantee [Member]
Schedule of Available-for-sale and Trading Securities [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions In Loss Position Greater than Twelve Months	13
Available-for-Sale Continuous Unrealized Loss Position more than 12 months, Aggregate Losses	27,400
USDA Securities [Member]
Schedule of Available-for-sale and Trading Securities [Line Items]
Trading Securities	51,102	58,344
USDA Securities [Member] | USDA Guarantee [Member]
Schedule of Available-for-sale and Trading Securities [Line Items]
Trading Securities Amortized Cost	52,724	60,345
Trading Securities	$ 51,102	$ 58,344
Trading Securities, Weighted-Average Yield	5.56%	5.60%