Loans and Allowance for Credit Losses - Past Due Loan Status and Non-Accrual Loans by Portfolio Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	$ 31,721	$ 27,463
Non- accrual	121,620	144,443
Net loans	21,351,094	20,279,547
Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	80,007	88,349
Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	18,850	20,805
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	21,098,896	19,998,487
Real estate - commercial mortgage
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	1,722	2,473
Non- accrual	44,805	70,161
Net loans	8,127,728	7,693,835
Real estate - commercial mortgage | Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	4,408	10,753
Real estate - commercial mortgage | Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,341	4,644
Real estate - commercial mortgage | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	8,075,452	7,605,804
Commercial and Industrial
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	1,068	1,172
Non- accrual	39,952	27,116
Net loans	4,545,552	4,473,004
Commercial and Industrial | Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	5,620	6,067
Commercial and Industrial | Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,656	2,289
Commercial and Industrial | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	4,497,256	4,436,360
Real estate – residential mortgage
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	21,205	20,215
Non- accrual	20,824	26,294
Net loans	5,325,923	4,737,279
Real estate – residential mortgage | Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	49,145	57,061
Real estate – residential mortgage | Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	10,838	8,209
Real estate – residential mortgage | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	5,223,911	4,625,500
Real-estate - home equity
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	5,326	2,704
Non- accrual	4,753	6,105
Net loans	1,047,184	1,102,838
Real-estate - home equity | Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	8,142	5,666
Real-estate - home equity | Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	2,075	2,444
Real-estate - home equity | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	1,026,888	1,085,919
Real-estate - construction
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	1,535	0
Non- accrual	1,341	1,368
Net loans	1,239,075	1,269,925
Real-estate - construction | Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	4,185	1,762
Real-estate - construction | Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	451	1,758
Real-estate - construction | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	1,231,563	1,265,037
Consumer
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	747	899
Non- accrual	52	92
Net loans	729,318	699,179
Consumer | Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	8,361	6,692
Consumer | Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	1,767	1,339
Consumer | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	718,391	690,157
Leases and other loans
Financing Receivable, Past Due [Line Items]
≥ 90 Days Past Due and Accruing	118	0
Non- accrual	9,893	13,307
Net loans	336,314	303,487
Leases and other loans | Financial Asset, 30 to 59 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	146	348
Leases and other loans | Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Total	722	122
Leases and other loans | Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Total	$ 325,435	$ 289,710