Summary of Significant Accounting Policies - Consolidation of Variable Interest Entities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	$ 8,817,783	$ 8,314,096
Debt securities of consolidated trusts held by third parties	24,067,063	22,758,533
Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Available-for-sale, at fair value	6,974,002	6,328,559
Investment securities:
Variable Interest Entity [Line Items]
Available-for-sale, at fair value	4,401,879	3,836,391
Agricultural Finance
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	7,375,158	6,846,993
Borrower remittances	9,300	32,800
Unamortized discount	(39,100)
Consolidated VIE \| On-Balance Sheet:
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	1,120,403	948,623
Debt securities of consolidated trusts held by third parties	1,090,539	981,379
Consolidated VIE \| Operating Segments \| On-Balance Sheet: \| Agricultural Finance
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	1,120,403	948,623
Debt securities of consolidated trusts held by third parties	1,090,539	981,379
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]
Available-for-sale, at fair value	29,471	42,298
Maximum exposure to loss	32,348	42,155
Unconsolidated VIE \| On-Balance Sheet: \| Investment securities:
Variable Interest Entity [Line Items]
Available-for-sale, at fair value	2,906,158	2,258,219
Maximum exposure to loss	3,083,631	2,246,272
Unconsolidated VIE \| Off-Balance Sheet:
Variable Interest Entity [Line Items]
Maximum exposure to loss	509,114	578,358
Unconsolidated VIE \| Operating Segments \| On-Balance Sheet: \| Agricultural Finance \| Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Available-for-sale, at fair value	29,471	42,298
Maximum exposure to loss	32,348	42,155
Unconsolidated VIE \| Operating Segments \| On-Balance Sheet: \| Agricultural Finance \| Investment securities:
Variable Interest Entity [Line Items]
Available-for-sale, at fair 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	509,114	578,358
Unconsolidated VIE \| Corporate, Non-Segment \| On-Balance Sheet: \| Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Available-for-sale, at fair value	0	0
Maximum exposure to loss	0	0
Unconsolidated VIE \| Corporate, Non-Segment \| On-Balance Sheet: \| Investment securities:
Variable Interest Entity [Line Items]
Available-for-sale, at fair value	2,906,158	2,258,219
Maximum exposure to loss	3,083,631	2,246,272
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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