Off-Balance Sheet Guarantees and Long Term Standby Purchase Commitments - Cash Flows from Off-balance sheet Guaranteed Securities (Details) (USD $)	9 Months Ended				9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Farmer Mac Guaranteed Securities [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Dec. 31, 2013 Farmer Mac Guaranteed Securities [Member] Variable Interest Entity, Not Primary Beneficiary [Member]	Sep. 30, 2014 Farmer Mac Guaranteed Securities, excluding AgVantage [Member]	Dec. 31, 2013 Farmer Mac Guaranteed Securities, excluding AgVantage [Member]	Sep. 30, 2014 Farmer Mac Guaranteed Securities AgVantage [Member]	Dec. 31, 2013 Farmer Mac Guaranteed Securities AgVantage [Member]	Sep. 30, 2014 Long-Term Standby Purchase Commitments [Member]	Dec. 31, 2013 Long-Term Standby Purchase Commitments [Member]	Sep. 30, 2014 Long-Term Standby Purchase Commitments On Or After January 1, 2003 [Member]	Dec. 31, 2013 Long-Term Standby Purchase Commitments On Or After January 1, 2003 [Member]
Long-term Purchase Commitment [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted			$ 1,680,694,000	$ 1,766,982,000					$ 2,300,000,000	$ 2,300,000,000
Proceeds from sale of Farmer Mac Guaranteed Securities	169,820,000	64,609,000
Guarantee Fees Received	2,449,000	3,572,000
Payments to Acquire Loans and Leases Held-for-investment	0	(6,667,000)
Guarantor Obligations, Current Carrying Value			$ 11,900,000	$ 13,400,000							$ 27,100,000	$ 26,300,000
Weighted average remaining maturity, Loans underlying guarantees not held by transferor					12 years 2 months 12 days	12 years 9 months 18 days	2 years 8 months 8 days	3 years 4 months 20 days	14 years 3 months 18 days	13 years 10 months 24 days