Allowance for Credit Losses - Aging of Analysis of Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 12,961,999	$ 13,279,097	$ 13,211,650
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	7,208	11,167
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	23,090	26,688
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	6,101	13,621
90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	12,416	17,182
Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	41,607	57,491
Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	12,920,392	13,221,606
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,087,099	3,019,507	2,743,242
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	740	2,108
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,195	2,585
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,195	604
Commercial and Industrial | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,318	2,626
Commercial and Industrial | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,708	5,815
Commercial and Industrial | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	2,083,391	3,013,692
Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,639,623	3,392,676	3,463,953
Loans and Leases Past Due 90 Days or More and Still Accruing Interest		882
Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	631	75
Commercial real estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		2,568
Commercial real estate | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		963
Commercial real estate | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	631	3,606
Commercial real estate | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,638,992	3,389,070
Construction
Financing Receivable, Recorded Investment, Past Due
Loans and leases	813,969	735,819	519,241
Loans and Leases Past Due 90 Days or More and Still Accruing Interest		93
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	162	779
Construction | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		376
Construction | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases		2,137
Construction | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	162	3,292
Construction | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	813,807	732,527
Lease financing
Financing Receivable, Recorded Investment, Past Due
Loans and leases	231,394	245,411	202,483
Lease financing | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	231,394	245,411
Residential Mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,083,367	3,690,218	4,662,175
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	987
Residential Mortgage | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,030	3,382
Residential Mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,002	4,125
Residential Mortgage | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5,617	3,372
Residential Mortgage | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	9,649	10,879
Residential Mortgage | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	4,073,718	3,679,339
Home equity Line
Financing Receivable, Recorded Investment, Past Due
Loans and leases	876,608	841,624
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	3,681	4,818
Home equity Line | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,538	1,375
Home equity Line | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	538	743
Home equity Line | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,681	4,818
Home equity Line | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	5,757	6,936
Home equity Line | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	870,851	834,688
Consumer
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,229,939	1,353,842	$ 1,620,556
Loans and Leases Past Due 90 Days or More and Still Accruing Interest	1,800	3,266
Consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	16,534	18,492
Consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	3,366	5,205
Consumer | 90 Days or Greater Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,800	3,266
Consumer | Total Past Due
Financing Receivable, Recorded Investment, Past Due
Loans and leases	21,700	26,963
Consumer | Current
Financing Receivable, Recorded Investment, Past Due
Loans and leases	1,208,239	1,326,879
Residential mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases	$ 4,083,367	3,690,218
Home equity
Financing Receivable, Recorded Investment, Past Due
Loans and leases		841,624
Home equity | Residential Mortgage
Financing Receivable, Recorded Investment, Past Due
Loans and leases		4,531,842
Consumer loans
Financing Receivable, Recorded Investment, Past Due
Loans and leases		$ 1,353,842