Loans and Allowance for Credit Losses - Collateral Dependent Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	$ 3,649,275		$ 3,565,023
ACL Allocation	54,921	$ 56,601	58,204	$ 54,020	$ 52,950	$ 50,940
Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	28,229,000		31,305
Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	1,082,000		135
Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	29,311,000		31,440
ACL Allocation	207,000		175
Agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	356	487	418	764	783	674
Agricultural \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	2,489,000		2,135
Agricultural \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		135
Agricultural \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	2,489,000		2,270
ACL Allocation	0		0
Commercial and financial
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	10,163	10,862	11,890	10,676	10,901	10,217
Commercial and financial \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	1,808,000		3,810
Commercial and financial \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	1,082,000		0
Commercial and financial \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	2,890,000		3,810
ACL Allocation	3,000		0
Construction, 1 to 4 family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	676	761	617	320	322	280
Construction, 1 to 4 family residential \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	366,000		51
Construction, 1 to 4 family residential \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Construction, 1 to 4 family residential \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	366,000		51
ACL Allocation	0		0
Construction, land development and commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	3,400	3,485	3,165	2,272	2,145	2,113
Construction, land development and commercial \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	2,681,000		3,294
Construction, land development and commercial \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Construction, land development and commercial \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	2,681,000		3,294
ACL Allocation	19,000		0
Mortgage, farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	1,919	1,930	2,478	3,330	3,469	3,252
Mortgage, farmland \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	6,360,000		3,125
Mortgage, farmland \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Mortgage, farmland \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	6,360,000		3,125
ACL Allocation	0		0
Mortgage, 1 to 4 family first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	20,253	20,974	20,959	19,561	18,639	18,210
Mortgage, 1 to 4 family first liens \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	9,239,000		10,900
Mortgage, 1 to 4 family first liens \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Mortgage, 1 to 4 family first liens \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	9,239,000		10,900
ACL Allocation	158,000		0
Mortgage, commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	9,300	9,251	9,855	8,251	8,137	7,525
Mortgage, commercial \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	3,192,000		3,799
Mortgage, commercial \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Mortgage, commercial \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	3,192,000		3,799
ACL Allocation	27,000		0
Mortgage, 1 to 4 family junior liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	5,281	5,517	5,639	5,030	4,642	4,719
Mortgage, 1 to 4 family junior liens \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	173,000		251
Mortgage, 1 to 4 family junior liens \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Mortgage, 1 to 4 family junior liens \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	173,000		251
ACL Allocation	0		0
Mortgage, multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	2,531	2,358	2,345	2,934	2,930	2,828
Mortgage, multi-family \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	1,921,000		3,765
Mortgage, multi-family \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Mortgage, multi-family \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	1,921,000		3,765
ACL Allocation	0		0
Loans to individuals
Accounts, Notes, Loans and Financing Receivable [Line Items]
ACL Allocation	1,030	$ 964	826	$ 870	$ 970	$ 1,109
Loans to individuals \| Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		175
Loans to individuals \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		0
Loans to individuals \| Total
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis of collateral dependent loans	0		175
ACL Allocation	$ 0		$ 175