Farmer Mac Guaranteed Securities and USDA Guaranteed Securities - Schedule of Held-to-maturity Securities (Details) (Farmer Mac Guarantee [Member], Farmer Mac Guaranteed Securities [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2014
Held-to-maturity Securities, Amortized Cost
Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount	$ 1,124
Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount	1,659,146
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,660,270
Held-to-maturity Securities [Member]
Held-to-maturity Securities, Fair Value
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	1,007
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	1,661,337
Held-to-maturity Securities, Fair Value	$ 1,662,344
Held to Maturity Securities Weighted Average Yield
Held-to-Maturity Securities, Debt Maturities, Next Twelve Months, Weighted-Average Yield	4.34%
Held-to-Maturity Securities, Debt Maturities, Year Two Through Five, Weighted-Average Yield	2.45%
Held-to-Maturity Securities, Debt Maturities, Weighted-Average Yield	2.45%