Farmer Mac Guaranteed Securities and USDA Securities - Schedule of Held-to-maturity Securities (Details) - Farmer Mac Guaranteed Securities and USDA Securities - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Amortized Cost
Due within one year	$ 445,889
Due after one year through five years	751,402
Due after five years through ten years	213,460
Due after ten years	2,070,436
Amortized Cost	3,481,187	$ 3,679,611
Fair Value
Due within one year	451,452
Due after one year through five years	777,980
Due after five years through ten years	220,404
Due after ten years	2,147,089
Total	$ 3,596,925	$ 3,749,184
Weighted- Average Yield
Due within one year	2.94%
Due after one year through five years	3.21%
Due after five years through ten years	3.17%
Due after ten years	3.39%
Total	3.28%