Allowance for Credit Losses - Past-Due Status (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 14,221,272	$ 14,092,012
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	4,469	3,234
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	34,923	46,065
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,875	10,934
90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	13,037	9,698
Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	52,835	66,697
Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	14,168,437	14,025,315
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,268,332	2,235,897
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	461	291
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,766	2,682
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5	769
Commercial and Industrial | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,617	1,441
Commercial and Industrial | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,388	4,892
Commercial and Industrial | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,263,944	2,231,005
Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,106,200	4,132,309
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	1,346
Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,421	4,505
Commercial real estate | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,073	727
Commercial real estate | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5,494	5,232
Commercial real estate | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,100,706	4,127,077
Construction
Financing Receivable, Recorded Investment, Past Due
Loans and leases	913,959	844,643
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	102
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	901	109
Construction | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	102
Construction | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,003	109
Construction | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	912,956	844,534
Lease financing
Financing Receivable, Recorded Investment, Past Due
Loans and leases	327,122	298,090
Lease financing | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	24
Lease financing | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	24
Lease financing | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	327,098	298,090
Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,318,742	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	893	3,681
Residential mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,355	1,983
Residential mortgage | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,399	2,572
Residential mortgage | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	7,647	8,236
Residential mortgage | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,311,095	4,294,552
Home equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,095,365	1,055,351
Home equity Line | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,149	5,161
Home equity Line | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	898	1,381
Home equity Line | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,343	2,072
Home equity Line | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	7,390	8,614
Home equity Line | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,087,975	1,046,737
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,191,552	1,222,934
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	2,502	2,885
Consumer Portfolio Segment [Member] | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	22,769	29,927
Consumer Portfolio Segment [Member] | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,617	6,801
Consumer Portfolio Segment [Member] | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,503	2,886
Consumer Portfolio Segment [Member] | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	26,889	39,614
Consumer Portfolio Segment [Member] | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,164,663	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	$ 1,095,365