Allowance for Credit Losses - Past-Due Status (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 14,362,832	$ 14,092,012
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	3,251	3,234
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	27,720	46,065
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	13,045	10,934
90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	10,827	9,698
Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	51,592	66,697
Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	14,311,240	14,025,315
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,187,831	2,235,897
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	599	291
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,318	2,682
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	899	769
Commercial and Industrial | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,606	1,441
Commercial and Industrial | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,823	4,892
Commercial and Industrial | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,184,008	2,231,005
Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,290,948	4,132,309
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	619
Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		4,505
Commercial real estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,278
Commercial real estate | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	619	727
Commercial real estate | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,897	5,232
Commercial real estate | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,287,051	4,127,077
Construction
Financing Receivable, Recorded Investment, Past Due
Loans and leases	913,837	844,643
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		109
Construction | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		109
Construction | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	913,837	844,534
Lease financing
Financing Receivable, Recorded Investment, Past Due
Loans and leases	332,400	298,090
Lease financing | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	332,400	298,090
Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,317,537	4,302,788
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	58	58
Residential mortgage | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,662	3,681
Residential mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,531	1,983
Residential mortgage | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,524	2,572
Residential mortgage | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	10,717	8,236
Residential mortgage | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,306,820	4,294,552
Home equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,138,163	1,055,351
Home equity Line | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,843	5,161
Home equity Line | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	404	1,381
Home equity Line | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,103	2,072
Home equity Line | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	7,350	8,614
Home equity Line | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,130,813	1,046,737
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,182,116	1,222,934
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	1,975	2,885
Consumer Portfolio Segment [Member] | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	19,897	29,927
Consumer Portfolio Segment [Member] | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,933	6,801
Consumer Portfolio Segment [Member] | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,975	2,886
Consumer Portfolio Segment [Member] | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	25,805	39,614
Consumer Portfolio Segment [Member] | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,156,311	1,183,320
Residential Lending: Residential Mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases		4,302,788
Home equity line
Financing Receivable, Recorded Investment, Past Due
Loans and leases		$ 1,055,351
Home equity line | Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 1,138,163