Loans - Changes in the Allowance for Losses (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance			$ 15,089,000
Provision for/(release of) losses	$ 1,073,000	$ (1,372,000)	1,620,000	$ (1,316,000)
Ending balance	16,748,000		16,748,000
Farm & Ranch
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	3,933,000	2,875,000	4,044,000	2,882,000
Provision for/(release of) losses	2,000	(610,000)	(109,000)	(533,000)
Charge-offs	0	0	0	(84,000)
Ending balance	3,935,000	2,265,000	3,935,000	2,265,000
Farm & Ranch | Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for/(release of) losses			1,100,000	0
Corporate AgFinance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	7,039,000	1,073,000	2,731,000	560,000
Provision for/(release of) losses	328,000	677,000	4,636,000	1,190,000
Charge-offs	0	0	0	0
Ending balance	7,367,000	1,750,000	7,367,000	1,750,000
Corporate AgFinance | Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for/(release of) losses			4,600,000	1,200,000
Agricultural Finance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	10,972,000	3,948,000	6,775,000	3,442,000
Provision for/(release of) losses	330,000	67,000	4,527,000	657,000
Charge-offs	0	0	0	(84,000)
Ending balance	11,302,000	4,015,000	11,302,000	4,015,000
Rural Infrastructure Finance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	4,701,000	9,622,000	8,314,000	10,599,000
Provision for/(release of) losses	745,000	(1,234,000)	(2,868,000)	(2,211,000)
Charge-offs	0	0	0	0
Ending balance	$ 5,446,000	$ 8,388,000	5,446,000	8,388,000
Rural Infrastructure Finance | Collateral Pledged
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Provision for/(release of) losses			$ 0	$ 0