Loans - Changes in the Allowance for Losses (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 14,041,000
Provision for/(release of) losses	1,323,000	$ (860,000)	$ 7,805,000
Charge-offs			(5,800,000)
Ending balance	15,089,000	14,041,000
Agricultural Finance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,442,000	3,745,000	10,454,000
Provision for/(release of) losses	3,417,000	(1,357,000)	2,959,000
Charge-offs	84,000		(5,759,000)
Recovery		1,054,000
Ending balance	6,775,000	3,442,000	3,745,000
Agricultural Finance | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			(3,909,000)
Agricultural Finance | Cumulative Effect, Period of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			6,545,000
Farm & Ranch
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	2,882,000	3,404,000	8,830,000
Provision for/(release of) losses	1,246,000	(1,576,000)	3,068,000
Charge-offs	84,000	0	(5,759,000)
Recovery	0	1,054,000
Ending balance	4,044,000	2,882,000	3,404,000
Farm & Ranch | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			(2,735,000)
Farm & Ranch | Cumulative Effect, Period of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			6,095,000
Farm & Ranch | Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for/(release of) losses	1,900,000	0
Corporate AgFinance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	560,000	341,000	1,624,000
Provision for/(release of) losses	2,171,000	219,000	(109,000)
Charge-offs	0	0	0
Recovery	0	0
Ending balance	2,731,000	560,000	341,000
Corporate AgFinance | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			(1,174,000)
Corporate AgFinance | Cumulative Effect, Period of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			450,000
Corporate AgFinance | Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for/(release of) losses	2,400,000	0
Rural Infrastructure Finance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	10,599,000	10,087,000	0
Provision for/(release of) losses	(2,285,000)	512,000	4,709,000
Charge-offs	0	0	0
Recovery	0	0
Ending balance	8,314,000	10,599,000	10,087,000
Rural Infrastructure Finance | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			5,378,000
Rural Infrastructure Finance | Cumulative Effect, Period of Adoption, Adjusted Balance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			$ 5,378,000
Rural Infrastructure Finance | Collateral Pledged
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for/(release of) losses	$ 0	$ 0