Guarantees - Schedule of Underlying Off-Balance Sheet Guaranteed Securities (Details) - Farmer Mac Guaranteed Securities - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Guarantee and commitment obligation		$ 1,780	$ 2,230
Weighted-average remaining maturity	9 years 9 months 18 days	9 years 6 months
AgVantage Securities
Guarantor Obligations [Line Items]
Weighted-average remaining maturity	5 years	4 years 2 months 12 days