Farmer Mac Guaranteed Securities and USDA Securities - Farmer Mac Guaranteed Securities and USDA Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Farmer Mac Guaranteed Securities and USDA Securities
Held-to-maturity:
Unpaid Principal Balance	$ 3,638,142	$ 4,207,531
Amortized Cost	3,679,611	4,262,792
Unrealized Gains	70,495	2,735
Unrealized Losses	(922)	(74,175)
Fair Value	3,749,184	4,191,352
Farmer Mac Guaranteed Securities
Held-to-maturity:
Unpaid Principal Balance	1,447,471	2,096,568
Amortized Cost	1,447,451	2,096,618
Unrealized Gains	16,139	2,735
Unrealized Losses	(164)	(11,948)
Fair Value	1,463,426	2,087,405
Available-for-sale:
Amortized Cost	7,016,971
Fair Value	7,143,025
USDA Securities:
Trading:
Fair Value	8,913	9,999
Held-to-Maturity Securities \| Farmer Mac Guaranteed Securities and USDA Securities
Held-to-maturity:
Unamortized Premium/(Discount)	41,469	55,261
Available-for-sale:
Unamortized Premium/(Discount)	41,469	55,261
Trading:
Unamortized Premium/(Discount)	41,469	55,261
Held-to-Maturity Securities \| Farmer Mac Guaranteed Securities
Held-to-maturity:
Unamortized Premium/(Discount)	(20)	50
Available-for-sale:
Unamortized Premium/(Discount)	(20)	50
Trading:
Unamortized Premium/(Discount)	(20)	50
Institutional Credit \| Farmer Mac Guaranteed Securities
Held-to-maturity:
Unpaid Principal Balance	1,415,584	2,069,185
Amortized Cost	1,415,410	2,068,991
Unrealized Gains	15,300	2,637
Unrealized Losses	(164)	(11,948)
Fair Value	1,430,546	2,059,680
Available-for-sale:
Unpaid Principal Balance	7,017,095	6,003,733
Amortized Cost	7,016,971	6,003,529
Unrealized Gains	161,316	22,335
Unrealized Losses	(35,262)	(51,367)
Fair Value	7,143,025	5,974,497
Institutional Credit \| Held-to-Maturity Securities \| Farmer Mac Guaranteed Securities
Held-to-maturity:
Unamortized Premium/(Discount)	(174)	(194)
Available-for-sale:
Unamortized Premium/(Discount)	(174)	(194)
Trading:
Unamortized Premium/(Discount)	(174)	(194)
Institutional Credit \| Available-for-Sale Securities \| Farmer Mac Guaranteed Securities
Held-to-maturity:
Unamortized Premium/(Discount)	(124)	(204)
Available-for-sale:
Unamortized Premium/(Discount)	(124)	(204)
Trading:
Unamortized Premium/(Discount)	(124)	(204)
USDA Guarantees
Held-to-maturity:
Unamortized Premium/(Discount)	(200)	(200)
Available-for-sale:
Unamortized Premium/(Discount)	(200)	(200)
Trading:
Unamortized Premium/(Discount)	(200)	(200)
USDA Guarantees \| Farmer Mac Guaranteed Securities
Held-to-maturity:
Unpaid Principal Balance	31,887	27,383
Amortized Cost	32,041	27,627
Unrealized Gains	839	98
Unrealized Losses	0	0
Fair Value	32,880	27,725
USDA Guarantees \| USDA Securities:
Held-to-maturity:
Unpaid Principal Balance	2,190,671	2,110,963
Amortized Cost	2,232,160	2,166,174
Unrealized Gains	54,356	0
Unrealized Losses	(758)	(62,227)
Fair Value	2,285,758	2,103,947
Trading:
Unpaid Principal Balance	8,400	9,591
Amortized Cost	8,879	10,292
Unrealized Gains	61	20
Unrealized Losses	(27)	(313)
Fair Value	$ 8,913	$ 9,999
Trading securities, weighted-average yield	5.20%	5.21%
USDA Guarantees \| Held-to-Maturity Securities \| Farmer Mac Guaranteed Securities
Held-to-maturity:
Unamortized Premium/(Discount)	$ 154	$ 244
Available-for-sale:
Unamortized Premium/(Discount)	154	244
Trading:
Unamortized Premium/(Discount)	154	244
USDA Guarantees \| Held-to-Maturity Securities \| USDA Securities:
Held-to-maturity:
Unamortized Premium/(Discount)	41,489	55,211
Available-for-sale:
Unamortized Premium/(Discount)	41,489	55,211
Trading:
Unamortized Premium/(Discount)	41,489	55,211
USDA Guarantees \| Trading Securities \| USDA Securities:
Held-to-maturity:
Unamortized Premium/(Discount)	479	701
Available-for-sale:
Unamortized Premium/(Discount)	479	701
Trading:
Unamortized Premium/(Discount)	$ 479	$ 701

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