Loans and Allowances for Credit Losses, By Aging Category (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	$ 52,504	$ 48,371
Current and Past Due Performing Loans	24,114,724	23,904,968
Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	23,953,419	23,705,831
30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	59,350	55,411
60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	21,775	50,082
90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	80,180	93,644
Commercial [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	0
Current and Past Due Performing Loans	15,030,136	14,803,769
Commercial [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	14,990,812	14,723,999
Commercial [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	28,845	18,433
Commercial [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	837	31,447
Commercial [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	9,642	29,890
Commercial [Member] | Healthcare [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	0
Current and Past Due Performing Loans	3,967,533	4,143,233
Commercial [Member] | Healthcare [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	3,932,142	4,071,336
Commercial [Member] | Healthcare [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	25,778	18,019
Commercial [Member] | Healthcare [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	30,290
Commercial [Member] | Healthcare [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	9,613	23,588
Commercial [Member] | Services [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	0
Current and Past Due Performing Loans	3,643,203	3,576,223
Commercial [Member] | Services [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	3,642,436	3,575,787
Commercial [Member] | Services [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	2
Commercial [Member] | Services [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	767	0
Commercial [Member] | Services [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	434
Commercial [Member] | Energy [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	0
Current and Past Due Performing Loans	3,254,724	3,437,101
Commercial [Member] | Energy [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	3,254,724	3,437,101
Commercial [Member] | Energy [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	0
Commercial [Member] | Energy [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	0
Commercial [Member] | Energy [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	0
Commercial [Member] | General business [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	0
Current and Past Due Performing Loans	4,164,676	3,647,212
Commercial [Member] | General business [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	4,161,510	3,639,775
Commercial [Member] | General business [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	3,067	412
Commercial [Member] | General business [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	70	1,157
Commercial [Member] | General business [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	29	5,868
Commercial real estate [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	3
Current and Past Due Performing Loans	5,058,452	5,337,647
Commercial real estate [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	5,048,667	5,327,481
Commercial real estate [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	2,992
Commercial real estate [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	0	0
Commercial real estate [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	9,785	7,174
Loans to individuals [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	52,504	48,368
Current and Past Due Performing Loans	4,026,136	3,763,552
Loans to individuals [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	3,913,940	3,654,351
Loans to individuals [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	30,505	33,986
Loans to individuals [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	20,938	18,635
Loans to individuals [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	60,753	56,580
Loans to individuals [Member] | Residential mortgage [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	36
Current and Past Due Performing Loans	2,436,958	2,160,640
Loans to individuals [Member] | Residential mortgage [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	2,416,633	2,149,927
Loans to individuals [Member] | Residential mortgage [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	10,930	6,340
Loans to individuals [Member] | Residential mortgage [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	5,622	1,494
Loans to individuals [Member] | Residential mortgage [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	3,773	2,879
Loans to individuals [Member] | Residential mortgage [Member] | US Government Agency Insured Loans
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	52,504	48,201
Current and Past Due Performing Loans	136,649	149,807
Loans to individuals [Member] | Residential mortgage [Member] | US Government Agency Insured Loans | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	45,910	54,122
Loans to individuals [Member] | Residential mortgage [Member] | US Government Agency Insured Loans | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	18,514	25,085
Loans to individuals [Member] | Residential mortgage [Member] | US Government Agency Insured Loans | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	15,268	17,053
Loans to individuals [Member] | Residential mortgage [Member] | US Government Agency Insured Loans | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	56,957	53,547
Loans to individuals [Member] | Personal [Member]
Financing Receivable, Past Due [Line Items]
Past Due 90 Days or More and Accruing	0	131
Current and Past Due Performing Loans	1,452,529	1,453,105
Loans to individuals [Member] | Personal [Member] | Current
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	1,451,397	1,450,302
Loans to individuals [Member] | Personal [Member] | 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	1,061	2,561
Loans to individuals [Member] | Personal [Member] | 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	48	88
Loans to individuals [Member] | Personal [Member] | 90 Days or More [Member]
Financing Receivable, Past Due [Line Items]
Current and Past Due Performing Loans	$ 23	$ 154