Farmer Mac Guaranteed Securities and USDA Guaranteed Securities - Schedule of Held-to-maturity Securities (Details) - Farmer Mac Guaranteed Securities [Member] $ in Thousands	Dec. 31, 2015 USD ($)
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
Held-to-maturity Securities, Debt Maturities, within One Year, Net Carrying Amount	$ 680,330
Held-to-maturity Securities, Debt Maturities, after One Through Five Years, Net Carrying Amount	593,686
Held-to-maturity Securities, Amortized Cost before Other than Temporary Impairment	1,274,016
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value [Abstract]
Held-to-maturity Securities, Debt Maturities, Next Twelve Months, Fair Value	680,956
Held-to-maturity Securities, Debt Maturities, Year Two Through Five, Fair Value	600,861
Held-to-maturity Securities, Fair Value	$ 1,281,817
Held-to-Maturity Securities, Debt Maturities, Weighted Average Yield, Single Maturity Date [Abstract]
Held-to-Maturity Securities, Debt Maturities, Next Twelve Months, Weighted-Average Yield	2.27%
Held-to-Maturity Securities, Debt Maturities, Year Two Through Five, Weighted-Average Yield	2.23%
Held-to-Maturity Securities, Debt Maturities, Weighted-Average Yield	2.25%