Allowance for Loan and Lease Losses - Aging of Analysis of Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 51,155	$ 58,614
Current	12,788,037	13,011,034
Total Accruing Loans and Leases	12,839,192	13,069,648
Total Non Accruing Loans and Leases	4,204	6,543
Total loans and leases	12,843,396	13,076,191
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	30,932	41,727
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	13,066	10,499
Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	7,157	6,388
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,380	1,434
Current	2,650,685	3,207,052
Total Accruing Loans and Leases	2,654,065	3,208,486
Total Non Accruing Loans and Leases	12	274
Total loans and leases	2,654,077	3,208,760
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,426	1,293
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,204
Commercial and Industrial | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	750	141
Commercial real estate
Financing Receivable, Recorded Investment, Past Due
Total Past Due	779
Current	3,308,577	2,989,125
Total Accruing Loans and Leases	3,309,356	2,989,125
Total Non Accruing Loans and Leases	33	1,658
Total loans and leases	3,309,389	2,990,783
Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	699
Commercial real estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	80
Construction
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,169	91
Current	483,808	626,666
Total Accruing Loans and Leases	486,977	626,757
Total loans and leases	486,977	626,757
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due		91
Construction | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,169
Lease financing
Financing Receivable, Recorded Investment, Past Due
Total Past Due		47
Current	167,874	147,722
Total Accruing Loans and Leases	167,874	147,769
Total loans and leases	167,874	147,769
Lease financing | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due		47
Residential Mortgage.
Financing Receivable, Recorded Investment, Past Due
Total Past Due	4,191	3,318
Current	3,663,274	3,519,172
Total Accruing Loans and Leases	3,667,465	3,522,490
Total Non Accruing Loans and Leases	3,959	4,611
Total loans and leases	3,671,424	3,527,101
Residential Mortgage. | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	2,499	2,274
Residential Mortgage. | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,553	1,012
Residential Mortgage. | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	139	32
Home equity line
Financing Receivable, Recorded Investment, Past Due
Total Past Due	6,074	9,233
Current	910,032	903,284
Total Accruing Loans and Leases	916,106	912,517
Total loans and leases	916,106	912,517
Home equity line | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,933	5,616
Home equity line | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	949	775
Home equity line | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,192	2,842
Consumer
Financing Receivable, Recorded Investment, Past Due
Total Past Due	33,562	44,491
Current	1,603,787	1,618,013
Total Accruing Loans and Leases	1,637,349	1,662,504
Total Non Accruing Loans and Leases	200
Total loans and leases	1,637,549	1,662,504
Consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	24,375	32,406
Consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	6,111	8,712
Consumer | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,076	3,373
Consumer loans | Consumer
Financing Receivable, Recorded Investment, Past Due
Total loans and leases	236,881	239,906
Consumer - Auto | Consumer
Financing Receivable, Recorded Investment, Past Due
Total loans and leases	1,051,366	1,078,132
Credit Cards | Consumer
Financing Receivable, Recorded Investment, Past Due
Total loans and leases	$ 349,302	$ 344,466