Loans - Allowance for Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for losses	$ 16,614		$ 15,089
Farm & Ranch
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for losses	3,910	$ 3,935	4,044	$ 2,112	$ 2,265	$ 2,882
Corporate AgFinance
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for losses	3,678	7,367	2,731	2,084	1,750	560
Agricultural Finance
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for losses	7,588	11,302	6,775	4,196	4,015	3,442
Rural Infrastructure Finance
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for losses	$ 9,026	$ 5,446	$ 8,314	$ 8,806	$ 8,388	$ 10,599