FAIR VALUE DISCLOSURES - Schedule of Unobservable Input Reconciliation (Details) - Level 3 - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 6,886,365	$ 5,648,034	$ 6,744,017	$ 5,539,404
Purchases	1,145,320	100,000	1,540,320	400,000
Settlements	(215,213)	(17,245)	(428,553)	(293,360)
Allowance for Losses	59	(6)	51	44
Realized and unrealized (losses)/gains included in Income	$ (36,913)	$ 37,741	$ (58,372)	$ 119,808
Fair Value Recurring Basis Unobservable Input Reconciliation Asset Gain Loss Statement Of Income Extensible List Not Disclosed Flag	Realized andunrealized (losses)/gains included in Income	Realized andunrealized gains/(losses) included in Income	Realized andunrealized gains included in Income	Realized andunrealized gains/(losses) included in Income
Unrealized (losses)/gains included in other comprehensive income	$ 1,803	$ (12,405)	$ (16,042)	$ (9,777)
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Net unrealized (losses)/gains on available-for-sale securities	Net unrealized (losses)/gains on available-for-sale securities	Net unrealized (losses)/gains on available-for-sale securities	Net unrealized (losses)/gains on available-for-sale securities
Ending Balance	$ 7,781,421	$ 5,756,119	$ 7,781,421	$ 5,756,119
Available-for-sale securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6,881,498	5,642,737	6,739,120	5,534,022
Purchases	1,145,320	100,000	1,540,320	400,000
Settlements	(215,141)	(17,160)	(428,398)	(293,189)
Allowance for Losses	59	(6)	51	44
Realized and unrealized (losses)/gains included in Income	(36,970)	37,812	(58,482)	119,878
Unrealized (losses)/gains included in other comprehensive income	1,803	(12,405)	(16,042)	(9,777)
Ending Balance	7,776,569	5,750,978	7,776,569	5,750,978
ABS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	44,586
Purchases	20,320
Settlements	(1)
Allowance for Losses	0
Realized and unrealized (losses)/gains included in Income	(612)
Unrealized (losses)/gains included in other comprehensive income	1,181
Ending Balance	65,474		65,474
Auction-rate certificates backed by Government guaranteed student loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		19,353	0	19,476
Purchases		0	65,320	0
Settlements		0	(1)	0
Allowance for Losses		(1)	0	(1)
Realized and unrealized (losses)/gains included in Income		0	(630)	0
Unrealized (losses)/gains included in other comprehensive income		123	785	0
Ending Balance		19,475		19,475
AgVantage
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6,828,759	5,614,512	6,730,917	5,505,531
Purchases	1,125,000	100,000	1,475,000	400,000
Settlements	(215,000)	(16,994)	(428,097)	(292,849)
Allowance for Losses	59	(5)	51	45
Realized and unrealized (losses)/gains included in Income	(36,358)	37,812	(57,852)	119,878
Unrealized (losses)/gains included in other comprehensive income	509	(12,435)	(17,050)	(9,715)
Ending Balance	7,702,969	5,722,890	7,702,969	5,722,890
Interest-Only Farmer Mac Guaranteed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	8,153	8,872	8,203	9,015
Purchases	0	0	0	0
Settlements	(140)	(166)	(300)	(340)
Allowance for Losses	0	0	0	0
Realized and unrealized (losses)/gains included in Income	0	0	0	0
Unrealized (losses)/gains included in other comprehensive income	113	(93)	223	(62)
Ending Balance	8,126	8,613	8,126	8,613
Other Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,867	5,297	4,897	5,382
Purchases	0	0	0	0
Settlements	(72)	(85)	(155)	(171)
Allowance for Losses	0	0	0	0
Realized and unrealized (losses)/gains included in Income	57	(71)	110	(70)
Unrealized (losses)/gains included in other comprehensive income	0	0	0	0
Ending Balance	$ 4,852	$ 5,141	$ 4,852	$ 5,141