Loans and Allowance for Credit Losses Past Due Loan Status and Non-Accrual Loans by Portfolio Segment (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Total	$ 24,012,539	$ 24,044,919
Non- accrual	182,942	189,293
Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	141,918	115,714
Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	56,474	34,218
Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	29,949	30,781
Current
Financing Receivable, Past Due [Line Items]
Total	23,601,256	23,674,913
Real estate - commercial mortgage
Financing Receivable, Past Due [Line Items]
Total	9,678,038	9,601,858
Non- accrual	84,035	99,497
Real estate - commercial mortgage \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	43,317	32,715
Real estate - commercial mortgage \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	25,366	16,684
Real estate - commercial mortgage \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	6,817	2,862
Real estate - commercial mortgage \| Current
Financing Receivable, Past Due [Line Items]
Total	9,518,503	9,450,100
Commercial and Industrial
Financing Receivable, Past Due [Line Items]
Total	4,541,765	4,605,589
Non- accrual	39,115	42,217
Commercial and Industrial \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	22,938	6,031
Commercial and Industrial \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	17,219	3,636
Commercial and Industrial \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	6,450	1,460
Commercial and Industrial \| Current
Financing Receivable, Past Due [Line Items]
Total	4,456,043	4,552,245
Real estate - residential mortgage
Financing Receivable, Past Due [Line Items]
Total	6,511,687	6,349,643
Non- accrual	25,817	25,400
Real estate - residential mortgage \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	57,073	59,593
Real estate - residential mortgage \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	8,997	5,946
Real estate - residential mortgage \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	11,886	20,501
Real estate - residential mortgage \| Current
Financing Receivable, Past Due [Line Items]
Total	6,407,914	6,238,203
Real estate - home equity
Financing Receivable, Past Due [Line Items]
Total	1,193,410	1,160,616
Non- accrual	7,079	8,591
Real estate - home equity \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	5,463	6,778
Real estate - home equity \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	843	1,057
Real estate - home equity \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	3,036	4,758
Real estate - home equity \| Current
Financing Receivable, Past Due [Line Items]
Total	1,176,989	1,139,432
Real-estate - construction
Financing Receivable, Past Due [Line Items]
Total	1,155,099	1,394,899
Non- accrual	24,852	1,746
Real-estate - construction \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	6,261	3,549
Real-estate - construction \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,855	5,163
Real-estate - construction \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	750	0
Real-estate - construction \| Current
Financing Receivable, Past Due [Line Items]
Total	1,121,381	1,384,441
Consumer
Financing Receivable, Past Due [Line Items]
Total	583,949	616,856
Non- accrual	6	8
Consumer \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	6,505	6,779
Consumer \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,982	1,627
Consumer \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	988	1,017
Consumer \| Current
Financing Receivable, Past Due [Line Items]
Total	574,468	607,425
Leases and other loans
Financing Receivable, Past Due [Line Items]
Total	348,591	315,458
Non- accrual	2,038	11,834
Leases and other loans \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	361	269
Leases and other loans \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	212	105
Leases and other loans \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	22	183
Leases and other loans \| Current
Financing Receivable, Past Due [Line Items]
Total	$ 345,958	$ 303,067