Allowance for Loan and Lease Losses - Aging of Analysis of Past Due Loans and Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 36,688	$ 35,360
Current	11,474,260	10,670,049
Total Accruing Loans and Leases	11,510,948	10,705,409
Total NonAccruing Loans and Leases	9,430	16,621
Total loans and leases	11,520,378	10,722,030	$ 10,023,590
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	28,728	25,573
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	4,692	4,765
Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,268	5,022
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,332	2,766
Current	3,235,538	3,050,731
Total Accruing Loans and Leases	3,236,870	3,053,497
Total NonAccruing Loans and Leases	2,730	3,958
Total loans and leases	3,239,600	3,057,455	2,697,142
Commercial and Industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	720	198
Commercial and Industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	163	72
Commercial and Industrial | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	449	2,496
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due
Total Past Due	475	351
Current	2,343,020	2,163,959
Total Accruing Loans and Leases	2,343,495	2,164,310
Total NonAccruing Loans and Leases		138
Total loans and leases	2,343,495	2,164,448	2,047,465
Commercial Real Estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	475
Commercial Real Estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due		190
Commercial Real Estate | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due		161
Construction
Financing Receivable, Recorded Investment, Past Due
Current	450,012	367,460
Total Accruing Loans and Leases	450,012	367,460
Total loans and leases	450,012	367,460	470,061
Lease Financing
Financing Receivable, Recorded Investment, Past Due
Total Past Due	83	215
Current	179,804	198,283
Total Accruing Loans and Leases	179,887	198,498
Total NonAccruing Loans and Leases	153	181
Total loans and leases	180,040	198,679	244,298
Lease Financing | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due		41
Lease Financing | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	83	174
Residential
Financing Receivable, Recorded Investment, Past Due
Total Past Due	11,842	12,327
Current	3,778,070	3,507,756
Total Accruing Loans and Leases	3,789,912	3,520,083
Total NonAccruing Loans and Leases	6,547	12,344
Total loans and leases	3,796,459	3,532,427	3,338,021
Residential | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	9,907	10,143
Residential | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	1,069	1,447
Residential | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	866	737
Consumer
Financing Receivable, Recorded Investment, Past Due
Total Past Due	22,956	19,701
Current	1,487,816	1,381,860
Total Accruing Loans and Leases	1,510,772	1,401,561
Total loans and leases	1,510,772	1,401,561	$ 1,226,603
Consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	17,626	15,191
Consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	3,460	3,056
Consumer | Greater Than or Equal to 90 Days Past Due
Financing Receivable, Recorded Investment, Past Due
Total Past Due	$ 1,870	$ 1,454