Guarantees and Commitments - Changes in Reserve for Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	$ 1,950
Release of losses	(110)	$ (944)
Ending balance	1,840
Agricultural Finance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	1,068	2,097
Release of losses	(75)	(731)
Ending balance	993	1,366
Rural Infrastructure Finance
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance	882	1,180
Release of losses	(35)	(213)
Ending balance	$ 847	$ 967