Allowance for Credit Losses - Aging of Analysis of Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 12,891,743	$ 12,961,999
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	4,444	7,208
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	22,588	23,090
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	6,830	6,101
90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	11,467	12,416
Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	40,885	41,607
Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	12,850,858	12,920,392
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,923,534	2,087,099
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	591	740
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,825	1,195
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,351	1,195
Commercial and Industrial | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,160	1,318
Commercial and Industrial | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	6,336	3,708
Commercial and Industrial | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,917,198	2,083,391
Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,759,980	3,639,623
Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,503	631
Commercial real estate | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	727
Commercial real estate | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,230	631
Commercial real estate | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,756,750	3,638,992
Construction
Financing Receivable, Recorded Investment, Past Due
Loans and leases	708,300	813,969
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	247	162
Construction | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	247	162
Construction | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	708,053	813,807
Lease financing
Financing Receivable, Recorded Investment, Past Due
Loans and leases	223,170	231,394
Lease financing | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	75
Lease financing | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	75
Lease financing | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	223,095	231,394
Residential. Mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,153,824	4,083,367
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	13	987
Residential. Mortgage | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,229	3,030
Residential. Mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,301	1,002
Residential. Mortgage | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5,665	5,617
Residential. Mortgage | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	8,195	9,649
Residential. Mortgage | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,145,629	4,073,718
Home equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	918,101	876,608
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	2,252	3,681
Home equity Line | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,640	1,538
Home equity Line | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	589	538
Home equity Line | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,252	3,681
Home equity Line | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,481	5,757
Home equity Line | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	913,620	870,851
Consumer
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,204,834	1,229,939
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	1,588	1,800
Consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	14,144	16,534
Consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,589	3,366
Consumer | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,588	1,800
Consumer | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	18,321	21,700
Consumer | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,186,513	1,208,239
Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,153,824	4,083,367
Home equity line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 918,101	$ 876,608