Summary of Significant Accounting Policies - Consolidation of Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	$ 8,314,096	$ 7,261,933
Debt securities of consolidated trusts held by third parties	22,758,533	21,795,677
Farmer Mac Guaranteed Securities
Variable Interest Entity [Line Items]
Fair Value	6,328,559	6,947,701
Investment securities:
Variable Interest Entity [Line Items]
Fair Value	3,836,391	3,853,692
Unamortized Premium/(Discount)	0	0
On-Balance Sheet: \| Consolidated VIE
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	948,623	1,287,045
Debt securities of consolidated trusts held by third parties	981,379	1,323,786
On-Balance Sheet: \| Farmer Mac Guaranteed Securities \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	42,298	34,537
Maximum exposure to loss	42,155	34,456
On-Balance Sheet: \| Investment securities: \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	2,258,219	1,918,672
Maximum exposure to loss	2,246,272	1,909,535
Off-balance sheet \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Maximum exposure to loss	578,358	378,610
Agricultural Finance
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	6,846,993	6,176,438
Borrower remittances	32,800	36,700
USDA Securities
Variable Interest Entity [Line Items]
Unamortized Premium/(Discount)		100
Operating Segments \| Agricultural Finance \| On-Balance Sheet: \| Consolidated VIE
Variable Interest Entity [Line Items]
Loans held for investment, at amortized cost	948,623	1,287,045
Debt securities of consolidated trusts held by third parties	981,379	1,323,786
Operating Segments \| Agricultural Finance \| On-Balance Sheet: \| Farmer Mac Guaranteed Securities \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Fair Value	42,298	34,537
Maximum exposure to loss	42,155	34,456
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	578,358	378,610
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	2,258,219	1,918,672
Maximum exposure to loss	2,246,272	1,909,535
Corporate \| Off-balance sheet \| Unconsolidated VIE
Variable Interest Entity [Line Items]
Maximum exposure to loss	$ 0	$ 0

Amount, after accumulated amortization, of debt discount (premium).

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