Summary of Significant Accounting Policies - Consolidation of Variable Interest Entities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	$ 8,481,310	$ 8,314,096
Debt securities of consolidated trusts held by third parties	23,319,158
Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Fair Value	6,600,246	6,328,559
Investment securities:
Variable Interest Entity [Line Items]
Fair Value	4,195,314	3,836,391
On-Balance Sheet: \| Consolidated VIE
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	888,200	948,623
Debt securities of consolidated trusts held by third parties	895,145	981,379
On-Balance Sheet: \| Farmer Mac Guaranteed Securities \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	37,018	42,298
Maximum exposure to loss	37,956	42,155
On-Balance Sheet: \| Investment securities: \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	2,430,613	2,258,219
Maximum exposure to loss	2,465,989	2,246,272
Off-Balance Sheet: \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Maximum exposure to loss	544,484	578,358
Agricultural Finance
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	6,932,229	6,846,993
Borrower remittances	6,900	32,800
Operating Segments \| Agricultural Finance \| On-Balance Sheet: \| Consolidated VIE
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	888,200	948,623
Debt securities of consolidated trusts held by third parties	895,145	981,379
Operating Segments \| Agricultural Finance \| On-Balance Sheet: \| Farmer Mac Guaranteed Securities \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	37,018	42,298
Maximum exposure to loss	37,956	42,155
Operating Segments \| Agricultural Finance \| On-Balance Sheet: \| Investment securities: \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	0	0
Maximum exposure to loss	0	0
Operating Segments \| Agricultural Finance \| Off-Balance Sheet: \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Maximum exposure to loss	544,484	578,358
Corporate \| On-Balance Sheet: \| Consolidated VIE
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
Corporate \| On-Balance Sheet: \| Farmer Mac Guaranteed Securities \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	0	0
Maximum exposure to loss	0	0
Corporate \| On-Balance Sheet: \| Investment securities: \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	2,430,613	2,258,219
Maximum exposure to loss	2,465,989	2,246,272
Corporate \| Off-Balance Sheet: \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Maximum exposure to loss	$ 0	$ 0

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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