Fair Value Disclosures - Unobservable Input Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Income	Net Income	Net Income
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent	Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 6,358,451	$ 6,973,567	$ 7,170,850
Purchases	3,411,665	1,161,912	974,237
Settlements	(1,531,464)	(1,617,039)	(1,400,130)
Allowance for Losses	(264)	31	(345)
Realized and unrealized losses included in Income	(553,825)	(176,180)	202,757
Unrealized losses included in Other Comprehensive Income	(52,076)	16,160	26,198
Ending Balance	7,632,487	6,358,451	6,973,567
Floating rate auction-rate certificates backed by Government guaranteed student loans | Floating Interest Rate | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,254	19,171	18,912
Purchases	0	0	0
Settlements	0	0	0
Allowance for Losses	19	(16)	(36)
Realized and unrealized losses included in Income	0	0	0
Unrealized losses included in Other Comprehensive Income	(246)	99	295
Ending Balance	19,027	19,254	19,171
Available-for-sale securities | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	19,254	19,171	18,912
Purchases	0	0	0
Settlements	0	0	0
Allowance for Losses	19	(16)	(36)
Realized and unrealized losses included in Income	0	0	0
Unrealized losses included in Other Comprehensive Income	(246)	99	295
Ending Balance	19,027	19,254	19,171
Farmer Mac Guaranteed Securities | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6,328,559	6,947,701	7,143,025
Purchases	3,411,665	1,155,675	974,237
Settlements	(1,527,978)	(1,614,861)	(1,397,861)
Allowance for Losses	(283)	47	(309)
Realized and unrealized losses included in Income	(552,907)	(176,064)	202,706
Unrealized losses included in Other Comprehensive Income	(51,830)	16,061	25,903
Ending Balance	7,607,226	6,328,559	6,947,701
Farmer Mac Guaranteed Securities | Level 3 | Recurring | AgVantage Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6,316,145	6,947,701	7,143,025
Purchases	3,411,665	1,143,115	974,237
Settlements	(1,526,303)	(1,614,598)	(1,397,861)
Allowance for Losses	(283)	47	(309)
Realized and unrealized losses included in Income	(552,907)	(176,064)	202,706
Unrealized losses included in Other Comprehensive Income	(48,938)	15,944	25,903
Ending Balance	7,599,379	6,316,145	6,947,701
Farmer Mac Guaranteed Securities | Level 3 | Recurring | Farmer Mac Guaranteed USDA Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	12,414	0
Purchases	0	12,560
Settlements	(1,675)	(263)
Allowance for Losses	0	0
Realized and unrealized losses included in Income	0	0
Unrealized losses included in Other Comprehensive Income	(2,892)	117
Ending Balance	7,847	12,414	0
USDA Securities: | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4,401	6,695	8,913
Purchases	0	0	0
Settlements	(2,583)	(2,178)	(2,269)
Allowance for Losses	0	0	0
Realized and unrealized losses included in Income	(51)	(116)	51
Unrealized losses included in Other Comprehensive Income	0	0	0
Ending Balance	1,767	4,401	6,695
Guarantee and commitment obligations: | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6,237	0
Purchases	0	6,237
Settlements	(903)	0
Allowance for Losses	0	0
Realized and unrealized losses included in Income	(867)	0
Unrealized losses included in Other Comprehensive Income	0	0
Ending Balance	4,467	6,237	0
Guarantee and commitment obligations: | Level 3 | Recurring | Guarantee Asset
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6,237	0
Purchases	0	6,237
Settlements	(903)	0
Allowance for Losses	0	0
Realized and unrealized losses included in Income	(867)	0
Unrealized losses included in Other Comprehensive Income	0	0
Ending Balance	$ 4,467	$ 6,237	$ 0