Guarantees and Commitments - Schedule of Underlying Off-Balance Sheet Guaranteed Securities (Details) - Farmer Mac Guaranteed USDA Securities - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Guarantor Obligations [Line Items]
Guarantee and commitment obligation	$ 6,961		$ 7,355
Weighted-average remaining maturity	21 years 8 months 12 days	21 years 8 months 12 days
AgVantage Securities
Guarantor Obligations [Line Items]
Weighted-average remaining maturity	2 years 8 months 12 days	3 years