Loans and Leases and the Allowance for Credit Losses - Schedule of Recorded Investment in Loans and Leases by Class and Credit Quality Indicator (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	$ 11,793,608	$ 10,990,892
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	5,016,867	4,213,827
Commercial | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	1,908,482	1,379,152
Commercial | Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	2,745,611	2,518,051
Commercial | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	250,943	194,170
Commercial | Lease Financing
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	111,831	122,454
Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		4,079,663
Commercial | Pass | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		1,306,040
Commercial | Pass | Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		2,463,858
Commercial | Pass | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		188,832
Commercial | Pass | Lease Financing
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		120,933
Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		58,323
Commercial | Special Mention | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		37,722
Commercial | Special Mention | Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		16,453
Commercial | Special Mention | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		4,148
Commercial | Classified
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		75,841
Commercial | Classified | Commercial and Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		35,390
Commercial | Classified | Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		37,740
Commercial | Classified | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		1,190
Commercial | Classified | Lease Financing
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		1,521
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	6,776,741	6,777,065
Consumer | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	417,090	489,606
Consumer | Residential Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	4,044,228	3,891,100
Consumer | Home Equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	1,605,486	1,676,073
Consumer | Automobile
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases	$ 709,937	720,286
Consumer | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		6,765,307
Consumer | Pass | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		488,113
Consumer | Pass | Residential Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		3,886,389
Consumer | Pass | Home Equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		1,671,468
Consumer | Pass | Automobile
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		719,337
Consumer | Classified
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		11,758
Consumer | Classified | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		1,493
Consumer | Classified | Residential Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		4,711
Consumer | Classified | Home Equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		4,605
Consumer | Classified | Automobile
Financing Receivable, Credit Quality Indicator [Line Items]
Total Recorded Investment in Loans and Leases		$ 949