Summary of Significant Accounting Policies - Consolidation of Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	$ 8,915,656	$ 9,008,979
Debt securities of consolidated trusts held by third parties	25,245,778	25,000,199
Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Carrying value	8,225,454	7,607,226
Investment securities:
Variable Interest Entity [Line Items]
Carrying value	4,647,464	4,579,564
Agricultural Finance
Variable Interest Entity [Line Items]
Borrower remittances	600	8,100
Unamortized discount	(94,600)	(37,700)
Consolidated VIE \| On-balance sheet
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	1,468,357	1,211,576
Debt securities of consolidated trusts held by third parties	1,374,332	1,181,948
Consolidated VIE \| Operating Segments \| On-balance sheet \| Agricultural Finance
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	1,468,357	1,211,576
Debt securities of consolidated trusts held by third parties	1,374,332	1,181,948
Consolidated VIE \| Corporate, Non-Segment \| On-balance sheet
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	0	0
Debt securities of consolidated trusts held by third parties	0	0
Unconsolidated VIE \| On-balance sheet \| Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Carrying value	28,447	28,466
Maximum exposure to loss	30,570	31,208
Unconsolidated VIE \| On-balance sheet \| Investment securities:
Variable Interest Entity [Line Items]
Carrying value	3,366,020	3,138,619
Maximum exposure to loss	3,540,724	3,341,427
Unconsolidated VIE \| Off-balance sheet
Variable Interest Entity [Line Items]
Maximum exposure to loss	488,094	500,953
Unconsolidated VIE \| Operating Segments \| On-balance sheet \| Agricultural Finance \| Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Carrying value	28,447	28,466
Maximum exposure to loss	30,570	31,208
Unconsolidated VIE \| Operating Segments \| On-balance sheet \| Agricultural Finance \| Investment securities:
Variable Interest Entity [Line Items]
Carrying value	0	0
Maximum exposure to loss	0	0
Unconsolidated VIE \| Operating Segments \| Off-balance sheet \| Agricultural Finance
Variable Interest Entity [Line Items]
Maximum exposure to loss	488,094	500,953
Unconsolidated VIE \| Corporate, Non-Segment \| On-balance sheet \| Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Carrying value	0	0
Maximum exposure to loss	0	0
Unconsolidated VIE \| Corporate, Non-Segment \| On-balance sheet \| Investment securities:
Variable Interest Entity [Line Items]
Carrying value	3,366,020	3,138,619
Maximum exposure to loss	3,540,724	3,341,427
Unconsolidated VIE \| Corporate, Non-Segment \| Off-balance sheet
Variable Interest Entity [Line Items]
Maximum exposure to loss	$ 0	$ 0

Amount, after accumulated amortization, of debt discount.

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