FAIR VALUE DISCLOSURES - Schedule of Unobservable Input Reconciliation (Details) - Level 3 - Recurring - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 5,648,685	$ 5,492,768	$ 5,540,222	$ 5,558,633
Purchases	100,000	225,000	400,000	275,000
Settlements	(17,341)	(281,132)	(293,631)	(345,522)
Allowance for Losses	(6)	30	44	58
Realized and unrealized gains (losses) included in Income	37,746	(6,546)	119,821	(87,256)
Unrealized gains/(losses) included in Other Comprehensive Income	(12,405)	(4,906)	(9,777)	24,301
Ending Balance	5,756,679	5,425,214	5,756,679	5,425,214
Available-for-sale securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,353	19,281	19,476	19,082
Purchases	0	0	0	0
Settlements	0	0	0	0
Allowance for Losses	(1)	1	(1)	2
Realized and unrealized gains (losses) included in Income	0	0	0	0
Unrealized gains/(losses) included in Other Comprehensive Income	123	196	0	394
Ending Balance	19,475	19,478	19,475	19,478
Floating rate auction-rate certificates backed by Government guaranteed student loans | Floating interest rate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,353	19,281	19,476	19,082
Purchases	0	0	0	0
Settlements	0	0	0	0
Allowance for Losses	(1)	1	(1)	2
Realized and unrealized gains (losses) included in Income	0	0	0	0
Unrealized gains/(losses) included in Other Comprehensive Income	123	196	0	394
Ending Balance	19,475	19,478	19,475	19,478
Farmer Mac Guaranteed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,623,384	5,466,688	5,514,546	5,532,479
Purchases	100,000	225,000	400,000	275,000
Settlements	(17,160)	(281,004)	(293,189)	(345,136)
Allowance for Losses	(5)	29	45	56
Realized and unrealized gains (losses) included in Income	37,812	(6,460)	119,878	(87,155)
Unrealized gains/(losses) included in Other Comprehensive Income	(12,528)	(5,102)	(9,777)	23,907
Ending Balance	5,731,503	5,399,151	5,731,503	5,399,151
Farmer Mac Guaranteed Securities | AgVantage
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,614,512	5,457,197	5,505,531	5,522,712
Purchases	100,000	225,000	400,000	275,000
Settlements	(16,994)	(280,833)	(292,849)	(344,788)
Allowance for Losses	(5)	29	45	56
Realized and unrealized gains (losses) included in Income	37,812	(6,460)	119,878	(87,155)
Unrealized gains/(losses) included in Other Comprehensive Income	(12,435)	(5,092)	(9,715)	24,016
Ending Balance	5,722,890	5,389,841	5,722,890	5,389,841
Farmer Mac Guaranteed Securities | Farmer Mac Guaranteed USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	8,872	9,491	9,015	9,767
Purchases	0	0	0	0
Settlements	(166)	(171)	(340)	(348)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in Income	0	0	0	0
Unrealized gains/(losses) included in Other Comprehensive Income	(93)	(10)	(62)	(109)
Ending Balance	8,613	9,310	8,613	9,310
USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	651	1,066	818	1,241
Purchases	0	0	0	0
Settlements	(96)	(43)	(271)	(216)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in Income	5	3	13	1
Unrealized gains/(losses) included in Other Comprehensive Income	0	0	0	0
Ending Balance	560	1,026	560	1,026
Guarantee and commitment obligations:
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,297	5,733	5,382	5,831
Purchases	0	0	0	0
Settlements	(85)	(85)	(171)	(170)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in Income	(71)	(89)	(70)	(102)
Unrealized gains/(losses) included in Other Comprehensive Income	0	0	0	0
Ending Balance	5,141	5,559	5,141	5,559
Guarantee and commitment obligations: | Guarantee Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,297	5,733	5,382	5,831
Purchases	0	0	0	0
Settlements	(85)	(85)	(171)	(170)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in Income	(71)	(89)	(70)	(102)
Unrealized gains/(losses) included in Other Comprehensive Income	0	0	0	0
Ending Balance	$ 5,141	$ 5,559	$ 5,141	$ 5,559