Allowance for Credit Losses - Past-Due Status (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 14,359,899	$ 14,353,497
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	3,765	3,496
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	35,251	62,245
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	8,383	6,541
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	16,541	12,736
Financial Asset, Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	60,175	81,522
Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	14,299,724	14,271,975
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,208,690	2,165,349
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	110	494
Commercial and Industrial | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,647	2,611
Commercial and Industrial | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	193	349
Commercial and Industrial | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,194	1,464
Commercial and Industrial | Financial Asset, Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,034	4,424
Commercial and Industrial | Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,205,656	2,160,925
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,305,017	4,340,243
Loans and Leases Past Due 90 Days or More and Still Accruing Interest		300
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases		196
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,085	300
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,085	496
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,301,932	4,339,747
Construction
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,017,649	900,292
Construction | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	375	25,191
Construction | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	447
Construction | Financial Asset, Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	822	25,191
Construction | Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,016,827	875,101
Finance Leases Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	425,190	379,809
Finance Leases Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	425,190	379,809
Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5,376,249
Consumer
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,027,104	1,109,901
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	1,835	2,702
Consumer | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	16,101	23,259
Consumer | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,852	3,897
Consumer | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,835	2,702
Consumer | Financial Asset, Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	20,788	29,858
Consumer | Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,006,316	1,080,043
Real Estate Loan [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,216,416	4,283,315
Real Estate Loan [Member] | Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,216,416	4,283,315
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	1,820
Real Estate Loan [Member] | Residential mortgage | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	14,812	5,244
Real Estate Loan [Member] | Residential mortgage | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,166	1,475
Real Estate Loan [Member] | Residential mortgage | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	6,887	4,720
Real Estate Loan [Member] | Residential mortgage | Financial Asset, Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	25,865	11,439
Real Estate Loan [Member] | Residential mortgage | Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,190,551	4,271,876
Residential Lending: Home Equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,159,833	1,174,588
Residential Lending: Home Equity Line | Home equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,159,833	1,174,588
Residential Lending: Home Equity Line | Home equity Line | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,316	5,940
Residential Lending: Home Equity Line | Home equity Line | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,172	624
Residential Lending: Home Equity Line | Home equity Line | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,093	3,550
Residential Lending: Home Equity Line | Home equity Line | Financial Asset, Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	6,581	10,114
Residential Lending: Home Equity Line | Home equity Line | Financial Asset, Not Past Due [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 1,153,252	$ 1,164,474