Guarantees - Significant Cash Flows Received From and Paid to Trusts (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Proceeds from sale of Farmer Mac Guaranteed Securities	$ 64,612	$ 199,396
Guarantee fees received	$ 1,136	$ 1,122

Cash received for fees during the current period. This element excludes cash proceeds from license fees.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3536-108585

Name:	us-gaap_ProceedsFromFeesReceived
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration