Loans and Leases - Commitments (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Loans and leases
Loan and lease commitments	$ 5,143,299	$ 5,121,811
Real estate
Loans and leases
Loan and lease commitments	1,439,923	1,476,518
Commercial and Industrial
Loans and leases
Loan and lease commitments	2,226,648	2,185,810
Commercial Real Estate | Real estate
Loans and leases
Loan and lease commitments	86,210	88,331
Construction | Real estate
Loans and leases
Loan and lease commitments	379,275	434,406
Residential | Real estate
Loans and leases
Loan and lease commitments	974,438	953,781
Consumer
Loans and leases
Loan and lease commitments	1,476,712	1,459,467
Lease Financing
Loans and leases
Loan and lease commitments	$ 16	$ 16