Allowance for Loan and Lease Losses - Aging of Analysis of Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 58,126	$ 58,614
Current	13,148,056	13,011,034
Total Accruing Loans and Leases	13,206,182	13,069,648
Total Non Accruing Loans and Leases	5,468	6,543
Total loans and leases	13,211,650	13,076,191	$ 12,277,369
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	36,228	41,727
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	9,748	10,499
Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	12,150	6,388
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,762	1,434
Current	2,739,448	3,207,052
Total Accruing Loans and Leases	2,743,210	3,208,486
Total Non Accruing Loans and Leases	32	274
Total loans and leases	2,743,242	3,208,760	3,135,266
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,525	1,293
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	808
Commercial and Industrial | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,429	141
Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,802
Current	3,460,121	2,989,125
Total Accruing Loans and Leases	3,463,923	2,989,125
Total Non Accruing Loans and Leases	30	1,658
Total loans and leases	3,463,953	2,990,783	2,667,597
Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,664
Commercial real estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,125
Commercial real estate | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,013
Construction
Financing Receivable, Recorded Investment, Past Due
Total Past Due	2,367	91
Current	516,874	626,666
Total Accruing Loans and Leases	519,241	626,757
Total loans and leases	519,241	626,757	632,911
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due		91
Construction | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	2,367
Lease financing
Financing Receivable, Recorded Investment, Past Due
Total Past Due		47
Current	202,483	147,722
Total Accruing Loans and Leases	202,483	147,769
Total loans and leases	202,483	147,769	165,066
Lease financing | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due		47
Residential
Financing Receivable, Recorded Investment, Past Due
Total loans and leases	4,662,175	4,439,618	4,090,053
Consumer
Financing Receivable, Recorded Investment, Past Due
Total Past Due	38,104	44,491
Current	1,582,452	1,618,013
Total Accruing Loans and Leases	1,620,556	1,662,504
Total loans and leases	1,620,556	1,662,504	$ 1,586,476
Consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	26,810	32,406
Consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	7,022	8,712
Consumer | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	4,272	3,373
Residential mortgage | Residential
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,731	3,318
Current	3,759,799	3,519,172
Total Accruing Loans and Leases	3,763,530	3,522,490
Total Non Accruing Loans and Leases	5,406	4,611
Total loans and leases	3,768,936	3,527,101
Residential mortgage | Residential | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,258	2,274
Residential mortgage | Residential | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	399	1,012
Residential mortgage | Residential | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	74	32
Home equity | Home equity Line
Financing Receivable, Recorded Investment, Past Due
Total Past Due	6,360	9,233
Current	886,879	903,284
Total Accruing Loans and Leases	893,239	912,517
Total loans and leases	893,239	912,517
Home equity | Home equity Line | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	2,971	5,616
Home equity | Home equity Line | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	394	775
Home equity | Home equity Line | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	2,995	2,842
Consumer loans | Consumer
Financing Receivable, Recorded Investment, Past Due
Total loans and leases	226,304	239,906
Consumer - Auto | Consumer
Financing Receivable, Recorded Investment, Past Due
Total loans and leases	1,040,468	1,078,132
Credit Cards | Consumer
Financing Receivable, Recorded Investment, Past Due
Total loans and leases	$ 353,784	$ 344,466