Allowance for Loan and Lease Losses - Aging of Analysis of Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 33,319	$ 36,688
Current	11,740,847	11,474,260
Total Accruing Loans and Leases	11,774,166	11,510,948
Total NonAccruing Loans and Leases	7,330	9,430
Total loans and leases	11,781,496	11,520,378
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	23,395	28,728
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	6,376	4,692
Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,548	3,268
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Total Past Due	2,781	1,332
Current	3,238,573	3,235,538
Total Accruing Loans and Leases	3,241,354	3,236,870
Total NonAccruing Loans and Leases	2,154	2,730
Total loans and leases	3,243,508	3,239,600
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,150	720
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,322	163
Commercial and Industrial | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	309	449
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due
Total Past Due	4,675	475
Current	2,527,578	2,343,020
Total Accruing Loans and Leases	2,532,253	2,343,495
Total loans and leases	2,532,253	2,343,495
Commercial Real Estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	4,675	475
Construction
Financing Receivable, Recorded Investment, Past Due
Total Past Due	587
Current	469,154	450,012
Total Accruing Loans and Leases	469,741	450,012
Total loans and leases	469,741	450,012
Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	235
Construction | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	352
Lease Financing
Financing Receivable, Recorded Investment, Past Due
Total Past Due	84	83
Current	168,119	179,804
Total Accruing Loans and Leases	168,203	179,887
Total NonAccruing Loans and Leases	153	153
Total loans and leases	168,356	180,040
Lease Financing | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	84	83
Residential
Financing Receivable, Recorded Investment, Past Due
Total Past Due	6,697	11,842
Current	3,852,789	3,778,070
Total Accruing Loans and Leases	3,859,486	3,789,912
Total NonAccruing Loans and Leases	5,023	6,547
Total loans and leases	3,864,509	3,796,459
Residential | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,912	9,907
Residential | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,348	1,069
Residential | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,437	866
Consumer
Financing Receivable, Recorded Investment, Past Due
Total Past Due	18,495	22,956
Current	1,484,634	1,487,816
Total Accruing Loans and Leases	1,503,129	1,510,772
Total loans and leases	1,503,129	1,510,772
Consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	13,423	17,626
Consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,354	3,460
Consumer | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 1,718	$ 1,870