Allowance for Credit Losses - Past-Due Status (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 14,320,208	$ 14,353,497
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	3,620	3,496
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	22,172	62,245
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	6,671	6,541
90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	15,388	12,736
Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	44,231	81,522
Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	14,275,977	14,271,975
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,189,875	2,165,349
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	529	494
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,713	2,611
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	162	349
Commercial and Industrial | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,470	1,464
Commercial and Industrial | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,345	4,424
Commercial and Industrial | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,186,530	2,160,925
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,301,300	4,340,243
Loans and Leases Past Due 90 Days or More and Still Accruing Interest		300
Commercial Real Estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		196
Commercial Real Estate | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,953	300
Commercial Real Estate | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,953	496
Commercial Real Estate | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,298,347	4,339,747
Construction
Financing Receivable, Recorded Investment, Past Due
Loans and leases	972,517	900,292
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	606
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		25,191
Construction | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	606
Construction | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	606	25,191
Construction | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	971,911	875,101
Lease financing
Financing Receivable, Recorded Investment, Past Due
Loans and leases	394,009	379,809
Lease financing | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	394,009	379,809
Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5,408,280
Consumer
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,054,227	1,109,901
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	2,126	2,702
Consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	15,606	23,259
Consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,873	3,897
Consumer | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,126	2,702
Consumer | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	20,605	29,858
Consumer | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,033,622	1,080,043
Residential Lending: Residential Mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,242,502	4,283,315
Residential Lending: Residential Mortgage | Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,242,502	4,283,315
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	359
Residential Lending: Residential Mortgage | Residential mortgage | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,857	5,244
Residential Lending: Residential Mortgage | Residential mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,742	1,475
Residential Lending: Residential Mortgage | Residential mortgage | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5,406	4,720
Residential Lending: Residential Mortgage | Residential mortgage | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	10,005	11,439
Residential Lending: Residential Mortgage | Residential mortgage | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,232,497	4,271,876
Residential Lending: Home Equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,165,778	1,174,588
Residential Lending: Home Equity Line | Home equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,165,778	1,174,588
Residential Lending: Home Equity Line | Home equity Line | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,996	5,940
Residential Lending: Home Equity Line | Home equity Line | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	894	624
Residential Lending: Home Equity Line | Home equity Line | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,827	3,550
Residential Lending: Home Equity Line | Home equity Line | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	6,717	10,114
Residential Lending: Home Equity Line | Home equity Line | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 1,159,061	$ 1,164,474