Loans - Allowance for Losses Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Losses [Line Items]
(Release of)/provision for losses	$ (860)	$ 7,805	$ 3,504
(Recovery)/charge-off from the allowance for losses		5,800
Agricultural Finance
Financing Receivable, Allowance for Credit Losses [Line Items]
(Release of)/provision for losses	(1,357)	2,959	3,504
(Recovery)/charge-off from the allowance for losses	0	5,759	67
Rural Infrastructure Finance
Financing Receivable, Allowance for Credit Losses [Line Items]
(Release of)/provision for losses	512	4,709	0
(Recovery)/charge-off from the allowance for losses	$ 0	$ 0	$ 0