Fair Value Disclosures - Summary of Carrying Value and Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financial assets:
Financial derivatives	$ 19,139	$ 16,123
Guarantee and commitment fees receivable	45,538	37,113
Financial liabilities:
Financial derivatives	160,271	182,371
Guarantee and commitment obligation	43,926	35,535	$ 36,700	$ 38,683
Fair Value
Financial assets:
Cash and cash equivalents	908,785	1,033,941
Loans	9,814,642	9,167,525
Financial derivatives	19,139	17,468
Guarantee and commitment fees receivable	42,533	34,115
Financial liabilities:
Notes payable	22,716,791	22,130,263
Debt securities of consolidated trusts held by third parties	1,005,306	1,390,330
Financial derivatives	34,248	29,892
Guarantee and commitment obligation	40,920	32,537
Fair Value | Investment securities:
Financial assets:
Marketable securities	3,884,202	3,899,925
Fair Value | Farmer Mac Guaranteed Securities
Financial assets:
Marketable securities	8,360,293	8,148,691
Fair Value | USDA Securities:
Financial assets:
Marketable securities	2,536,473	2,637,509
Carrying Amount
Financial assets:
Cash and cash equivalents	908,785	1,033,941
Loans	9,248,678	8,535,146
Financial derivatives	19,139	17,468
Guarantee and commitment fees receivable	45,538	37,113
Financial liabilities:
Notes payable	22,716,156	21,848,917
Debt securities of consolidated trusts held by third parties	981,379	1,323,786
Financial derivatives	34,248	29,892
Guarantee and commitment obligation	43,926	35,535
Carrying Amount | Investment securities:
Financial assets:
Marketable securities	3,882,590	3,898,724
Carrying Amount | Farmer Mac Guaranteed Securities
Financial assets:
Marketable securities	8,361,798	8,123,493
Carrying Amount | USDA Securities:
Financial assets:
Marketable securities	$ 2,440,732	$ 2,480,321