Farmer Mac Guaranteed Securities and USDA Securities - Schedule of Held-to-maturity Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Institutional Credit
Weighted- Average Yield
Held-to-maturity, accrued interest excluded	$ 31,200	$ 44,700
Farmer Mac Guaranteed Securities and USDA Securities
Amortized Cost
Due within one year	329,849
Due after one year through five years	741,605
Due after five years through ten years	250,695
Due after ten years	2,164,508
Amortized Cost	3,486,657	$ 3,649,538
Fair Value
Due within one year	332,601
Due after one year through five years	750,667
Due after five years through ten years	253,347
Due after ten years	2,184,368
Total	$ 3,520,983
Weighted- Average Yield
Due within one year	2.71%
Due after one year through five years	2.51%
Due after five years through ten years	2.75%
Due after ten years	3.11%
Total	2.90%