Fair Value Disclosures - Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Income	Net Income	Net Income	Net Income
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 8,250,460	$ 6,628,731	$ 7,632,487	$ 6,358,451
Purchases	852,000	520,000	1,539,650	1,352,750
Settlements	(1,258,093)	(515,028)	(1,400,530)	(811,898)
Allowance for Losses	9	85	45	(331)
Realized and unrealized (losses)/gains included in Income	(101,929)	(149,490)	(8,228)	(359,984)
Unrealized gains included in Other Comprehensive Income	27,679	(7,114)	6,702	(61,804)
Ending Balance	7,770,126	6,477,184	7,770,126	6,477,184
Floating rate auction-rate certificates backed by Government guaranteed student loans \| Floating Interest Rate \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,031	18,961	19,027	19,254
Purchases	0	0	0	0
Settlements	0	0	0	0
Allowance for Losses	1	1	5	3
Realized and unrealized (losses)/gains included in Income	0	0	0	0
Unrealized gains included in Other Comprehensive Income	0	99	0	(196)
Ending Balance	19,032	19,061	19,032	19,061
Available-for-sale securities \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,031	18,961	19,027	19,254
Purchases	0	0	0	0
Settlements	0	0	0	0
Allowance for Losses	1	1	5	3
Realized and unrealized (losses)/gains included in Income	0	0	0	0
Unrealized gains included in Other Comprehensive Income	0	99	0	(196)
Ending Balance	19,032	19,061	19,032	19,061
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	8,225,454	6,600,246	7,607,226	6,328,559
Purchases	852,000	520,000	1,539,650	1,352,750
Settlements	(1,257,854)	(513,700)	(1,399,673)	(809,363)
Allowance for Losses	8	84	40	(334)
Realized and unrealized (losses)/gains included in Income	(101,872)	(149,205)	(8,530)	(359,792)
Unrealized gains included in Other Comprehensive Income	27,679	(7,213)	6,702	(61,608)
Ending Balance	7,745,415	6,450,212	7,745,415	6,450,212
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring \| AgVantage Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	8,217,420	6,589,224	7,599,379	6,316,145
Purchases	852,000	520,000	1,539,650	1,352,750
Settlements	(1,257,413)	(513,342)	(1,398,799)	(808,626)
Allowance for Losses	8	84	40	(334)
Realized and unrealized (losses)/gains included in Income	(101,872)	(149,205)	(8,530)	(359,792)
Unrealized gains included in Other Comprehensive Income	27,667	(6,365)	6,070	(59,747)
Ending Balance	7,737,810	6,440,396	7,737,810	6,440,396
Farmer Mac Guaranteed Securities \| Level 3 \| Recurring \| Farmer Mac Guaranteed USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	8,034	11,022	7,847	12,414
Purchases	0	0	0	0
Settlements	(441)	(358)	(874)	(737)
Allowance for Losses	0	0	0	0
Realized and unrealized (losses)/gains included in Income	0	0	0	0
Unrealized gains included in Other Comprehensive Income	12	(848)	632	(1,861)
Ending Balance	7,605	9,816	7,605	9,816
USDA Securities: \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,405	3,386	1,767	4,401
Purchases	0	0	0	0
Settlements	(48)	(1,140)	(435)	(2,092)
Allowance for Losses	0	0	0	0
Realized and unrealized (losses)/gains included in Income	(9)	29	16	(34)
Unrealized gains included in Other Comprehensive Income	0	0	0	0
Ending Balance	1,348	2,275	1,348	2,275
Guarantee and commitment obligations: \| Level 3 \| Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,570	6,138	4,467	6,237
Purchases	0	0	0	0
Settlements	(191)	(188)	(422)	(443)
Allowance for Losses	0	0	0	0
Realized and unrealized (losses)/gains included in Income	(48)	(314)	286	(158)
Unrealized gains included in Other Comprehensive Income	0	0	0	0
Ending Balance	4,331	5,636	4,331	5,636
Guarantee and commitment obligations: \| Level 3 \| Recurring \| Guarantee Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,570	6,138	4,467	6,237
Purchases	0	0	0	0
Settlements	(191)	(188)	(422)	(443)
Allowance for Losses	0	0	0	0
Realized and unrealized (losses)/gains included in Income	(48)	(314)	286	(158)
Unrealized gains included in Other Comprehensive Income	0	0	0	0
Ending Balance	$ 4,331	$ 5,636	$ 4,331	$ 5,636

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Allowance for Credit Loss

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of gain (loss) recognized in other comprehensive income (OCI) from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

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-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-SubTopic 10
-Topic 820
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482106/820-10-50-2

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- Definition

Indicates line item in statement in which net income is reported that includes gain (loss) from asset measured at fair value using unobservable input (level 3).

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