Guarantees and Commitments - Schedule of Underlying Off-Balance Sheet Guaranteed Securities (Details) - Farmer Mac Guaranteed Securities - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2021	Dec. 31, 2020
Guarantor Obligations [Line Items]
Guarantee and commitment obligation	$ 1,257	$ 1,625
Weighted-average remaining maturity	8 years 10 months 24 days	9 years 6 months
AgVantage Securities
Guarantor Obligations [Line Items]
Weighted-average remaining maturity	3 years 2 months 12 days	4 years

The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=124440162&loc=d3e12069-110248

Name:	us-gaap_GuaranteeObligationsCurrentCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant