FAIR VALUE DISCLOSURES - Schedule of Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Assets:
AFS investment securities	$ 14,885,573	$ 13,580,285
Financial derivatives	19,912	44,875
Other Assets	4,683	4,897
Total Assets at fair value	14,910,168	13,630,057
Liabilities:
Financial derivatives	219,897	21,618
Total Liabilities at fair value	219,897	21,618
Total AFS Investment Securities
Assets:
AFS investment securities	14,885,573	13,580,285
Government/GSE guaranteed MBS
Assets:
AFS investment securities	5,762,016	5,297,018
U.S. Treasuries
Assets:
AFS investment securities	1,561,091	1,544,147
ABS
Assets:
AFS investment securities	61,026
AgVantage
Assets:
AFS investment securities	7,493,597	6,730,917
Interest-Only Farmer Mac Guaranteed Securities
Assets:
AFS investment securities	7,843	8,203
Level 1
Assets:
Financial derivatives	0	154
Other Assets	0	0
Total Assets at fair value	1,561,091	1,544,301
Liabilities:
Financial derivatives	44	15
Total Liabilities at fair value	44	15
Level 1 | Total AFS Investment Securities
Assets:
AFS investment securities	1,561,091	1,544,147
Level 1 | Government/GSE guaranteed MBS
Assets:
AFS investment securities	0	0
Level 1 | U.S. Treasuries
Assets:
AFS investment securities	1,561,091	1,544,147
Level 1 | ABS
Assets:
AFS investment securities	0
Level 1 | AgVantage
Assets:
AFS investment securities	0	0
Level 1 | Interest-Only Farmer Mac Guaranteed Securities
Assets:
AFS investment securities	0	0
Level 2
Assets:
Financial derivatives	19,912	44,721
Other Assets	0	0
Total Assets at fair value	5,781,928	5,341,739
Liabilities:
Financial derivatives	219,853	21,603
Total Liabilities at fair value	219,853	21,603
Level 2 | Total AFS Investment Securities
Assets:
AFS investment securities	5,762,016	5,297,018
Level 2 | Government/GSE guaranteed MBS
Assets:
AFS investment securities	5,762,016	5,297,018
Level 2 | U.S. Treasuries
Assets:
AFS investment securities	0	0
Level 2 | ABS
Assets:
AFS investment securities	0
Level 2 | AgVantage
Assets:
AFS investment securities	0	0
Level 2 | Interest-Only Farmer Mac Guaranteed Securities
Assets:
AFS investment securities	0	0
Level 3
Assets:
Financial derivatives	0	0
Other Assets	4,683	4,897
Total Assets at fair value	7,567,149	6,744,017
Liabilities:
Financial derivatives	0	0
Total Liabilities at fair value	$ 0	$ 0
Percent of level three fair value assets and liabilities	19.00%	19.00%
Financial instruments level three percent	51.00%	49.00%
Level 3 | Total AFS Investment Securities
Assets:
AFS investment securities	$ 7,562,466	$ 6,739,120
Level 3 | Government/GSE guaranteed MBS
Assets:
AFS investment securities	0	0
Level 3 | U.S. Treasuries
Assets:
AFS investment securities	0	0
Level 3 | ABS
Assets:
AFS investment securities	61,026
Level 3 | AgVantage
Assets:
AFS investment securities	7,493,597	6,730,917
Level 3 | Interest-Only Farmer Mac Guaranteed Securities
Assets:
AFS investment securities	$ 7,843	$ 8,203