Loans and Allowance for Credit Losses Past Due Loan Status and Non-Accrual Loans by Portfolio Segment (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Past Due [Line Items]
Total	$ 23,862,574	$ 24,044,919
Non- accrual	162,426	189,293
Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	126,012	115,714
Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	39,477	34,218
Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	34,367	30,781
Current
Financing Receivable, Past Due [Line Items]
Total	23,500,292	23,674,913
Real estate - commercial mortgage
Financing Receivable, Past Due [Line Items]
Total	9,676,517	9,601,858
Non- accrual	86,528	99,497
Real estate - commercial mortgage \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	37,443	32,715
Real estate - commercial mortgage \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	20,827	16,684
Real estate - commercial mortgage \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,553	2,862
Real estate - commercial mortgage \| Current
Financing Receivable, Past Due [Line Items]
Total	9,530,166	9,450,100
Commercial and Industrial
Financing Receivable, Past Due [Line Items]
Total	4,531,266	4,605,589
Non- accrual	34,569	42,217
Commercial and Industrial \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	10,622	6,031
Commercial and Industrial \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	8,747	3,636
Commercial and Industrial \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	8,344	1,460
Commercial and Industrial \| Current
Financing Receivable, Past Due [Line Items]
Total	4,468,984	4,552,245
Real estate - residential mortgage
Financing Receivable, Past Due [Line Items]
Total	6,409,657	6,349,643
Non- accrual	27,226	25,400
Real estate - residential mortgage \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	38,253	59,593
Real estate - residential mortgage \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	6,369	5,946
Real estate - residential mortgage \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	19,652	20,501
Real estate - residential mortgage \| Current
Financing Receivable, Past Due [Line Items]
Total	6,318,157	6,238,203
Real estate - home equity
Financing Receivable, Past Due [Line Items]
Total	1,170,470	1,160,616
Non- accrual	8,124	8,591
Real estate - home equity \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	7,905	6,778
Real estate - home equity \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	916	1,057
Real estate - home equity \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	3,461	4,758
Real estate - home equity \| Current
Financing Receivable, Past Due [Line Items]
Total	1,150,064	1,139,432
Real-estate - construction
Financing Receivable, Past Due [Line Items]
Total	1,175,445	1,394,899
Non- accrual	3,666	1,746
Real-estate - construction \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	25,891	3,549
Real-estate - construction \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	499	5,163
Real-estate - construction \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	0	0
Real-estate - construction \| Current
Financing Receivable, Past Due [Line Items]
Total	1,145,389	1,384,441
Consumer
Financing Receivable, Past Due [Line Items]
Total	597,305	616,856
Non- accrual	7	8
Consumer \| Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	5,537	6,779
Consumer \| Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,977	1,627
Consumer \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,090	1,017
Consumer \| Current
Financing Receivable, Past Due [Line Items]
Total	588,694	607,425
Leases and other loans
Financing Receivable, Past Due [Line Items]
Total	301,914	315,458
Non- accrual	2,306	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	142	105
Leases and other loans \| Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	267	183
Leases and other loans \| Current
Financing Receivable, Past Due [Line Items]
Total	$ 298,838	$ 303,067