FINANCIAL DERIVATIVES - Schedule of Net Income/(Expense) Recognized (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative Instruments, Gain (Loss) [Line Items]
Investments and cash equivalents	$ 84,924	$ 59,703
Interest Income Farmer Mac Guaranteed Securities and USDA Securities	166,813
Interest Income Loans	144,580	119,032
Total interest expense	(309,949)	(236,214)
Gains on financial derivatives	2,079	399
Total	88,447
Interest expense on interest rate swaps	7,314	5,355
Designated as hedge
Derivative Instruments, Gain (Loss) [Line Items]
Investments and cash equivalents		59,703
Interest Income Farmer Mac Guaranteed Securities and USDA Securities		136,537
Interest Income Loans		119,032
Total interest expense		(236,214)
Gains on financial derivatives		399
Total		79,457
Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(28,182)	(6,835)
Premium/discount amortization recognized on hedged items	(302)	(423)
Recognized on hedged items	(99,836)	54,981
Gains/(losses) on fair value hedging relationships	3,002	(105)
Designated as hedge | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	(14)	(14)
Interest settlements reclassified from AOCI into net income on derivatives	5,431	4,391
Recognized on hedged items	(8,091)	(7,190)
Expense recognized on cash flow hedges	(2,674)	(2,813)
No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	2,079	399
Interest Income Investments and Cash Equivalents | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	9,948	6,961
Premium/discount amortization recognized on hedged items	445	268
Recognized on hedged items	(27,521)	27,428
Gains/(losses) on fair value hedging relationships	268	275
Interest Income Investments and Cash Equivalents | Designated as hedge | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0
Recognized on hedged items	0	0
Expense recognized on cash flow hedges	0	0
Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	51,705	41,971
Premium/discount amortization recognized on hedged items	0	0
Recognized on hedged items	(80,743)	93,295
Gains/(losses) on fair value hedging relationships	843	(497)
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Designated as hedge | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0
Recognized on hedged items	0	0
Expense recognized on cash flow hedges	0	0
Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Interest Income Loans | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	16,598	15,208
Premium/discount amortization recognized on hedged items	0	0
Recognized on hedged items	(47,061)	56,957
Gains/(losses) on fair value hedging relationships	1,119	276
Interest Income Loans | Designated as hedge | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0
Recognized on hedged items	0	0
Expense recognized on cash flow hedges	0	0
Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Total Interest Expense | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	(106,433)	(70,975)
Premium/discount amortization recognized on hedged items	(747)	(691)
Recognized on hedged items	55,489	(122,699)
Gains/(losses) on fair value hedging relationships	772	(159)
Total Interest Expense | Designated as hedge | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	(14)	(14)
Interest settlements reclassified from AOCI into net income on derivatives	5,431	4,391
Recognized on hedged items	(8,091)	(7,190)
Expense recognized on cash flow hedges	(2,674)	(2,813)
Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Gains on financial derivatives | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on hedged items	0	0
Premium/discount amortization recognized on hedged items	0	0
Recognized on hedged items	0	0
Gains/(losses) on fair value hedging relationships	0	0
Gains on financial derivatives | Designated as hedge | Cash flow hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Premium/discount amortization recognized on hedged items	0	0
Interest settlements reclassified from AOCI into net income on derivatives	0	0
Recognized on hedged items	0	0
Expense recognized on cash flow hedges	0	0
Gains on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	2,079	399
Interest Rate Swap | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(15,073)	(28,829)
Income/(expense) related to interest settlements on fair value hedging relationships	(43,557)	(36,087)
Recognized on derivatives	102,838	(55,086)
Interest Rate Swap | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	754	33
Interest expense on interest rate swaps	(34)	(1,625)
Interest Rate Swap | Interest Income Investments and Cash Equivalents | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	10,297	6,549
Income/(expense) related to interest settlements on fair value hedging relationships	20,690	13,778
Recognized on derivatives	27,789	(27,153)
Interest Rate Swap | Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Interest expense on interest rate swaps	0	0
Interest Rate Swap | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	40,332	28,909
Income/(expense) related to interest settlements on fair value hedging relationships	92,037	70,880
Recognized on derivatives	81,586	(93,792)
Interest Rate Swap | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Interest expense on interest rate swaps	0	0
Interest Rate Swap | Interest Income Loans | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	17,849	13,180
Income/(expense) related to interest settlements on fair value hedging relationships	34,447	28,388
Recognized on derivatives	48,180	(56,681)
Interest Rate Swap | Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Interest expense on interest rate swaps	0	0
Interest Rate Swap | Total Interest Expense | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	(83,551)	(77,467)
Income/(expense) related to interest settlements on fair value hedging relationships	(190,731)	(149,133)
Recognized on derivatives	(54,717)	122,540
Interest Rate Swap | Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Interest expense on interest rate swaps	0	0
Interest Rate Swap | Gains on financial derivatives | Designated as hedge | Fair value hedges:
Derivative Instruments, Gain (Loss) [Line Items]
Recognized on derivatives	0	0
Income/(expense) related to interest settlements on fair value hedging relationships	0	0
Recognized on derivatives	0	0
Interest Rate Swap | Gains on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	754	33
Interest expense on interest rate swaps	(34)	(1,625)
Treasury futures | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	1,359	1,991
Treasury futures | Interest Income Investments and Cash Equivalents | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Treasury futures | Interest Income Farmer Mac Guaranteed Securities and USDA Securities | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Treasury futures | Interest Income Loans | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Treasury futures | Total Interest Expense | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	0	0
Treasury futures | Gains on financial derivatives | No hedge designation
Derivative Instruments, Gain (Loss) [Line Items]
Gains on financial derivatives	$ 1,359	$ 1,991