Loans and Leases - Commitments (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Loans and leases
Loan and lease commitments	$ 5,154,215	$ 5,121,811
Real estate
Loans and leases
Loan and lease commitments	1,492,331	1,476,518
Commercial and Industrial
Loans and leases
Loan and lease commitments	2,180,122	2,185,810
Commercial Real Estate | Real estate
Loans and leases
Loan and lease commitments	83,774	88,331
Construction | Real estate
Loans and leases
Loan and lease commitments	417,633	434,406
Residential | Real estate
Loans and leases
Loan and lease commitments	990,924	953,781
Consumer
Loans and leases
Loan and lease commitments	1,481,746	1,459,467
Lease Financing
Loans and leases
Loan and lease commitments	$ 16	$ 16