Loans - Schedule of Composition of Loan Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 10,977,162		$ 10,549,845
Allowance for losses	(16,614)		(15,089)
Total loans, net of allowance	10,537,173		10,205,466
Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	10,977,162		10,549,845
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	(423,375)		(329,290)
Total	10,553,787		10,220,555
Allowance for losses	(16,614)		(15,089)
Total loans, net of allowance	10,537,173		10,205,466
Farm & Ranch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,410,672		6,362,326
Allowance for losses	(3,910)	$ (3,935)	(4,044)	$ (2,112)	$ (2,265)	$ (2,882)
Farm & Ranch | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,410,672		6,362,326
Corporate AgFinance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,223,777		1,166,253
Allowance for losses	(3,678)	(7,367)	(2,731)	(2,084)	(1,750)	(560)
Corporate AgFinance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,223,777		1,166,253
Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	7,634,449		7,528,579
Allowance for losses	(7,588)	(11,302)	(6,775)	(4,196)	(4,015)	(3,442)
Agricultural Finance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	7,634,449		7,528,579
Rural Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,342,713		3,021,266
Allowance for losses	(9,026)	$ (5,446)	(8,314)	$ (8,806)	$ (8,388)	$ (10,599)
Rural Infrastructure Finance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,342,713		3,021,266
Unsecuritized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	9,554,308		9,338,269
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	(423,375)		(329,290)
Total	9,130,933		9,008,979
Allowance for losses	(16,162)		(14,629)
Total loans, net of allowance	9,114,771		8,994,350
Unsecuritized | Farm & Ranch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	4,987,818		5,150,750
Unsecuritized | Corporate AgFinance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,223,777		1,166,253
Unsecuritized | Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,211,595		6,317,003
Unsecuritized | Rural Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	3,342,713		3,021,266
In Consolidated Trusts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,422,854		1,211,576
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	0		0
Total	1,422,854		1,211,576
Allowance for losses	(452)		(460)
Total loans, net of allowance	1,422,402		1,211,116
In Consolidated Trusts | Farm & Ranch
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,422,854		1,211,576
In Consolidated Trusts | Corporate AgFinance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	0		0
In Consolidated Trusts | Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,422,854		1,211,576
In Consolidated Trusts | Rural Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 0		$ 0