Loans - Schedule of Composition of Loan Balances (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 10,260,851		$ 9,236,129
Allowance for losses	(13,002)		(14,041)
Total loans, net of allowance	9,925,184		9,248,678
Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	10,260,851		9,236,129
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	(322,665)		26,590
Total	9,938,186		9,262,719
Allowance for losses	(13,002)		(14,041)
Total loans, net of allowance	9,925,184		9,248,678
Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	7,375,158		6,846,993
Allowance for losses	(4,196)	$ (4,015)	(3,442)	$ (3,506)	$ (3,092)	$ (3,745)
Agricultural Finance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	7,375,158		6,846,993
Rural Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,885,693		2,389,136
Allowance for losses	(8,806)	$ (8,388)	(10,599)	$ (10,788)	$ (10,908)	$ (10,087)
Rural Infrastructure Finance | Real Estate Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,885,693		2,389,136
Unsecuritized
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	9,140,448		8,287,506
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	(322,665)		26,590
Total	8,817,783		8,314,096
Allowance for losses	(12,599)		(13,477)
Total loans, net of allowance	8,805,184		8,300,619
Unsecuritized | Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	6,254,755		5,898,370
Unsecuritized | Rural Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	2,885,693		2,389,136
In Consolidated Trusts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,120,403		948,623
Unamortized premiums, discounts, fair value hedge basis adjustment, and other cost basis adjustments	0		0
Total	1,120,403		948,623
Allowance for losses	(403)		(564)
Total loans, net of allowance	1,120,000		948,059
In Consolidated Trusts | Agricultural Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,120,403		948,623
In Consolidated Trusts | Rural Infrastructure Finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 0		$ 0