FAIR VALUE DISCLOSURES - Schedule of Unobservable Input Reconciliation (Details) - Level 3 - Recurring - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 5,756,679	$ 5,425,214	$ 5,540,222	$ 5,558,633
Purchases	350,000	400,000	750,000	675,000
Settlements	(249,873)	(216,315)	(543,505)	(561,836)
Allowance for Losses	60	44	104	102
Realized and unrealized gains (losses) included in income	19,287	189,288	139,109	102,032
Unrealized gains included in Other Comprehensive Income	2,932	(10,664)	(6,845)	13,636
Ending Balance	5,879,085	5,787,567	5,879,085	5,787,567
Available-for-sale securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,475	19,478	19,476	19,082
Purchases	0	0	0	0
Settlements	0	0	0	0
Allowance for Losses	7	0	6	2
Realized and unrealized gains (losses) included in income	0	0	0	0
Unrealized gains included in Other Comprehensive Income	0	0	0	394
Ending Balance	19,482	19,478	19,482	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	19,475	19,478	19,476	19,082
Purchases	0	0	0	0
Settlements	0	0	0	0
Allowance for Losses	7	0	6	2
Realized and unrealized gains (losses) included in income	0	0	0	0
Unrealized gains included in Other Comprehensive Income	0	0	0	394
Ending Balance	19,482	19,478	19,482	19,478
Farmer Mac Guaranteed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,731,503	5,399,151	5,514,546	5,532,479
Purchases	350,000	400,000	750,000	675,000
Settlements	(249,680)	(216,031)	(542,869)	(561,166)
Allowance for Losses	53	44	98	100
Realized and unrealized gains (losses) included in income	19,290	189,191	139,168	102,036
Unrealized gains included in Other Comprehensive Income	2,932	(10,664)	(6,845)	13,242
Ending Balance	5,854,098	5,761,691	5,854,098	5,761,691
Farmer Mac Guaranteed Securities | AgVantage
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,722,890	5,389,841	5,505,531	5,522,712
Purchases	350,000	400,000	750,000	675,000
Settlements	(249,516)	(215,855)	(542,365)	(560,643)
Allowance for Losses	53	44	98	100
Realized and unrealized gains (losses) included in income	19,290	189,191	139,168	102,036
Unrealized gains included in Other Comprehensive Income	2,925	(10,836)	(6,790)	13,180
Ending Balance	5,845,642	5,752,385	5,845,642	5,752,385
Farmer Mac Guaranteed Securities | Farmer Mac Guaranteed USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	8,613	9,310	9,015	9,767
Purchases	0	0	0	0
Settlements	(164)	(176)	(504)	(523)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in income	0	0	0	0
Unrealized gains included in Other Comprehensive Income	7	172	(55)	62
Ending Balance	8,456	9,306	8,456	9,306
USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	560	1,026	818	1,241
Purchases	0	0	0	0
Settlements	(109)	(198)	(381)	(414)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in income	5	14	19	15
Unrealized gains included in Other Comprehensive Income	0	0	0	0
Ending Balance	456	842	456	842
Guarantee and commitment obligations:
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,141	5,559	5,382	5,831
Purchases	0	0	0	0
Settlements	(84)	(86)	(255)	(256)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in income	(8)	83	(78)	(19)
Unrealized gains included in Other Comprehensive Income	0	0	0	0
Ending Balance	5,049	5,556	5,049	5,556
Guarantee and commitment obligations: | Guarantee Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5,141	5,559	5,382	5,831
Purchases	0	0	0	0
Settlements	(84)	(86)	(255)	(256)
Allowance for Losses	0	0	0	0
Realized and unrealized gains (losses) included in income	(8)	83	(78)	(19)
Unrealized gains included in Other Comprehensive Income	0	0	0	0
Ending Balance	$ 5,049	$ 5,556	$ 5,049	$ 5,556