LOANS - Schedule of Composition of Loan Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Jun. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	$ 15,721,111		$ 13,609,172
Allowance for losses	(35,340)		(23,223)
Total loans, net of allowance	15,361,990		13,204,638
Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	15,721,111		13,609,172
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	(323,781)		(381,311)
Total loans	15,397,330		13,227,861
Allowance for losses	(35,340)		(23,223)
Total loans, net of allowance	15,361,990		13,204,638
Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	9,572,831		8,834,689
Allowance for losses	(18,262)	$ (13,578)	(10,511)	$ (10,601)	$ (8,690)	$ (6,884)
Agricultural Finance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	9,572,831		8,834,689
Allowance for losses	(18,262)		(10,511)
Farm & Ranch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	8,120,433		7,453,015
Allowance for losses	(11,134)	(6,635)	(5,132)	(4,832)	(4,676)	(3,936)
Farm & Ranch | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	8,120,433		7,453,015
Allowance for losses	(11,134)		(5,132)
Corporate AgFinance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	1,452,398		1,381,674
Allowance for losses	(7,128)	(6,943)	(5,379)	(5,769)	(4,014)	(2,948)
Corporate AgFinance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	1,452,398		1,381,674
Allowance for losses	(7,128)		(5,379)
Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	6,148,280		4,774,483
Allowance for losses	(17,078)	$ (16,378)	(12,712)	$ (9,350)	$ (7,810)	$ (9,147)
Infrastructure Finance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	6,148,280		4,774,483
Allowance for losses	(17,078)		(12,712)
Unsecuritized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	13,515,898		11,570,889
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	(323,781)		(381,311)
Total loans	13,192,117		11,189,578
Allowance for losses	(34,517)		(22,594)
Total loans, net of allowance	13,157,600		11,166,984
Unsecuritized | Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	7,367,618		6,796,406
Unsecuritized | Farm & Ranch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	5,915,220		5,414,732
Unsecuritized | Corporate AgFinance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	1,452,398		1,381,674
Unsecuritized | Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	6,148,280		4,774,483
In Consolidated Trusts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	2,205,213		2,038,283
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	0		0
Total loans	2,205,213		2,038,283
Allowance for losses	(823)		(629)
Total loans, net of allowance	2,204,390		2,037,654
In Consolidated Trusts | Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	2,205,213		2,038,283
In Consolidated Trusts | Farm & Ranch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	2,205,213		2,038,283
In Consolidated Trusts | Corporate AgFinance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	0		0
In Consolidated Trusts | Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total unpaid principal balance	$ 0		$ 0