FAIR VALUE DISCLOSURES - Summary of Carrying Value and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Financial assets:
Financial derivatives	$ 32,667	$ 27,789
Guarantee and commitment fees receivable	50,775	50,499
Financial liabilities:
Financial derivatives	29,161	77,326
Guarantee and commitment obligation	48,426	48,326
Fair Value
Financial assets:
Cash and cash equivalents	901,023	1,024,007
Loans	15,297,680	12,924,604
Financial derivatives	32,667	27,789
Guarantee and commitment fees receivable	57,634	57,562
Financial liabilities:
Notes payable	28,824,748	26,759,873
Debt securities of consolidated trusts held by third parties	2,125,993	1,910,302
Financial derivatives	29,161	77,326
Guarantee and commitment obligation	55,284	55,388
Fair Value | Investment securities
Financial assets:
Marketable securities	6,679,390	5,973,571
Fair Value | Farmer Mac Guaranteed Securities
Financial assets:
Marketable securities	7,548,248	8,215,646
Fair Value | USDA Securities
Financial assets:
Marketable securities	2,249,616	2,113,342
Carrying Amount
Financial assets:
Cash and cash equivalents	901,023	1,024,007
Loans	15,361,990	13,204,638
Financial derivatives	32,667	27,789
Guarantee and commitment fees receivable	50,775	50,499
Financial liabilities:
Notes payable	29,196,780	27,371,174
Debt securities of consolidated trusts held by third parties	2,089,042	1,929,628
Financial derivatives	29,161	77,326
Guarantee and commitment obligation	48,426	48,326
Carrying Amount | Investment securities
Financial assets:
Marketable securities	6,679,104	5,973,301
Carrying Amount | Farmer Mac Guaranteed Securities
Financial assets:
Marketable securities	7,546,699	8,232,234
Carrying Amount | USDA Securities
Financial assets:
Marketable securities	$ 2,389,636	$ 2,371,352