Fair Value Disclosures - Fair Value Measurements, Recurring and Nonrecurring (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets:
Financial derivatives	$ 28,855	$ 37,409
Liabilities:
Financial derivatives	188,362	175,326
Investment securities:
Assets:
Fair Value	4,873,414	$ 4,579,564
Farmer Mac Guaranteed Securities
Assets:
Fair Value	$ 5,058,697
Level 3
Liabilities:
Percent of level three fair value assets and liabilities	18.00%	28.00%
Financial instruments level three percent	50.00%	62.00%
Recurring
Assets:
Financial derivatives	$ 28,855	$ 37,409
Guarantee Asset	5,963	4,467
Total Assets at fair value	9,968,231	12,230,433
Liabilities:
Financial derivatives	188,362	175,326
Total Liabilities at fair value	188,362	175,326
Recurring | USDA Securities:
Assets:
Trading	1,302	1,767
Recurring | Investment securities:
Assets:
Fair Value	4,873,414	4,579,564
Recurring | Farmer Mac Guaranteed Securities
Assets:
Fair Value	5,058,697	7,607,226
Recurring | Level 1
Assets:
Financial derivatives	81	0
Guarantee Asset	0	0
Total Assets at fair value	1,002,539	1,119,611
Liabilities:
Financial derivatives	12	142
Total Liabilities at fair value	12	142
Recurring | Level 1 | USDA Securities:
Assets:
Trading	0	0
Recurring | Level 1 | Investment securities:
Assets:
Fair Value	1,002,458	1,119,611
Recurring | Level 1 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	0	0
Recurring | Level 2
Assets:
Financial derivatives	28,774	37,409
Guarantee Asset	0	0
Total Assets at fair value	3,880,697	3,478,335
Liabilities:
Financial derivatives	188,350	175,184
Total Liabilities at fair value	188,350	175,184
Recurring | Level 2 | USDA Securities:
Assets:
Trading	0	0
Recurring | Level 2 | Investment securities:
Assets:
Fair Value	3,851,923	3,440,926
Recurring | Level 2 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	0	0
Recurring | Level 3
Assets:
Financial derivatives	0	0
Guarantee Asset	5,963	4,467
Total Assets at fair value	5,084,995	7,632,487
Liabilities:
Financial derivatives	0	0
Total Liabilities at fair value	0	0
Recurring | Level 3 | USDA Securities:
Assets:
Trading	1,302	1,767
Recurring | Level 3 | Investment securities:
Assets:
Fair Value	19,033	19,027
Recurring | Level 3 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	5,058,697	7,607,226
AgVantage | Recurring | Farmer Mac Guaranteed Securities
Assets:
Fair Value	5,048,708	7,599,379
AgVantage | Recurring | Level 1 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	0	0
AgVantage | Recurring | Level 2 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	0	0
AgVantage | Recurring | Level 3 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	5,048,708	7,599,379
Farmer Mac Guaranteed USDA Securities | Recurring | Farmer Mac Guaranteed Securities
Assets:
Fair Value	9,989	7,847
Farmer Mac Guaranteed USDA Securities | Recurring | Level 1 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	0	0
Farmer Mac Guaranteed USDA Securities | Recurring | Level 2 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	0	0
Farmer Mac Guaranteed USDA Securities | Recurring | Level 3 | Farmer Mac Guaranteed Securities
Assets:
Fair Value	9,989	7,847
USDA Securities | Recurring | USDA Securities:
Assets:
Trading	1,302	1,767
USDA Securities | Recurring | Level 1 | USDA Securities:
Assets:
Trading	0	0
USDA Securities | Recurring | Level 2 | USDA Securities:
Assets:
Trading	0	0
USDA Securities | Recurring | Level 3 | USDA Securities:
Assets:
Trading	1,302	1,767
Floating Interest Rate | Floating rate auction-rate certificates backed by Government guaranteed student loans
Assets:
Fair Value	19,033	19,027
Floating Interest Rate | Guaranteed mortgage-backed securities
Assets:
Fair Value	2,465,545	2,392,540
Floating Interest Rate | Fixed rate U.S. Treasuries
Assets:
Fair Value	50,011
Floating Interest Rate | Recurring | Floating rate auction-rate certificates backed by Government guaranteed student loans
Assets:
Fair Value	19,033	19,027
Floating Interest Rate | Recurring | Guaranteed mortgage-backed securities
Assets:
Fair Value	2,465,545	2,392,540
Floating Interest Rate | Recurring | Floating rate U.S. Treasuries
Assets:
Fair Value	50,011
Floating Interest Rate | Recurring | Level 1 | Floating rate auction-rate certificates backed by Government guaranteed student loans
Assets:
Fair Value	0	0
Floating Interest Rate | Recurring | Level 1 | Guaranteed mortgage-backed securities
Assets:
Fair Value	0	0
Floating Interest Rate | Recurring | Level 1 | Floating rate U.S. Treasuries
Assets:
Fair Value	50,011
Floating Interest Rate | Recurring | Level 2 | Floating rate auction-rate certificates backed by Government guaranteed student loans
Assets:
Fair Value	0	0
Floating Interest Rate | Recurring | Level 2 | Guaranteed mortgage-backed securities
Assets:
Fair Value	2,465,545	2,392,540
Floating Interest Rate | Recurring | Level 2 | Floating rate U.S. Treasuries
Assets:
Fair Value	0
Floating Interest Rate | Recurring | Level 3 | Floating rate auction-rate certificates backed by Government guaranteed student loans
Assets:
Fair Value	19,033	19,027
Floating Interest Rate | Recurring | Level 3 | Guaranteed mortgage-backed securities
Assets:
Fair Value	0	0
Floating Interest Rate | Recurring | Level 3 | Floating rate U.S. Treasuries
Assets:
Fair Value	0
Fixed Interest Rate | Guaranteed mortgage-backed securities
Assets:
Fair Value	1,386,378	1,048,386
Fixed Interest Rate | Fixed rate U.S. Treasuries
Assets:
Fair Value	952,447	1,119,611
Fixed Interest Rate | Recurring | Guaranteed mortgage-backed securities
Assets:
Fair Value	1,386,378	1,048,386
Fixed Interest Rate | Recurring | Fixed rate U.S. Treasuries
Assets:
Fair Value	952,447	1,119,611
Fixed Interest Rate | Recurring | Level 1 | Guaranteed mortgage-backed securities
Assets:
Fair Value	0	0
Fixed Interest Rate | Recurring | Level 1 | Fixed rate U.S. Treasuries
Assets:
Fair Value	952,447	1,119,611
Fixed Interest Rate | Recurring | Level 2 | Guaranteed mortgage-backed securities
Assets:
Fair Value	1,386,378	1,048,386
Fixed Interest Rate | Recurring | Level 2 | Fixed rate U.S. Treasuries
Assets:
Fair Value	0	0
Fixed Interest Rate | Recurring | Level 3 | Guaranteed mortgage-backed securities
Assets:
Fair Value	0	0
Fixed Interest Rate | Recurring | Level 3 | Fixed rate U.S. Treasuries
Assets:
Fair Value	$ 0	$ 0