Related Party Transactions - Schedule of Related Party Transactions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Zions Bancorporation, National Association | Sales of Farmer Mac Guaranteed Securities
Related Party Transaction [Line Items]
Sales of Farmer Mac Guaranteed Securities	$ 0	$ 41,247	$ 163,134
Zions Bancorporation, National Association | USDA Guarantee | USDA Securities:
Related Party Transaction [Line Items]
Unpaid principal balance	9,565	10,764	8,875
Zions Bancorporation, National Association | Mortgages | Farm & Ranch
Related Party Transaction [Line Items]
Unpaid principal balance	214,319	177,143	129,040
CFC | AgVantage Securities | Guarantee Obligations
Related Party Transaction [Line Items]
Unpaid principal balance	1,450,000	250,000	575,000
CFC | AgVantage Securities | Revolving Credit Facility | Off-balance sheet
Related Party Transaction [Line Items]
Unpaid principal balance	321	19,500	0
CFC | AgVantage Securities | US Government-sponsored Enterprises Debt Securities
Related Party Transaction [Line Items]
Unpaid principal balance	1,577,438	542,443	660,000
CFC | Real Estate Loan
Related Party Transaction [Line Items]
Unpaid principal balance	$ 127,117	$ 272,943	$ 85,000