Allowance for Loan and Lease Losses - Disaggregation by Impairment Methodology (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Allowance for loan and lease losses:
Individually evaluated for impairment	$ 897	$ 1,092
Collectively evaluated for impairment	134,950	134,402
Total allowance for loan and lease losses	135,847	135,494	$ 137,154	$ 135,484
Loans and leases:
Individually evaluated for impairment	58,088	59,428
Collectively evaluated for impairment	11,723,408	11,460,950
Total loans and leases	11,781,496	11,520,378
Commercial Lending
Loans and leases:
Total loans and leases	6,413,858	6,213,147
Commercial and Industrial
Allowance for loan and lease losses:
Individually evaluated for impairment	213	380
Collectively evaluated for impairment	31,344	32,749
Total allowance for loan and lease losses	31,557	33,129	35,027	34,025
Loans and leases:
Individually evaluated for impairment	28,244	27,572
Collectively evaluated for impairment	3,215,264	3,212,028
Total loans and leases	3,243,508	3,239,600
Commercial Real Estate
Allowance for loan and lease losses:
Individually evaluated for impairment	7	7
Collectively evaluated for impairment	19,925	18,441
Total allowance for loan and lease losses	19,932	18,448	18,504	18,489
Loans and leases:
Individually evaluated for impairment	12,316	12,545
Collectively evaluated for impairment	2,519,937	2,330,950
Total loans and leases	2,532,253	2,343,495
Construction
Allowance for loan and lease losses:
Collectively evaluated for impairment	4,532	4,513
Total allowance for loan and lease losses	4,532	4,513	4,514	3,793
Loans and leases:
Collectively evaluated for impairment	469,741	450,012
Total loans and leases	469,741	450,012
Lease Financing
Allowance for loan and lease losses:
Collectively evaluated for impairment	813	847
Total allowance for loan and lease losses	813	847	807	888
Loans and leases:
Individually evaluated for impairment	153	153
Collectively evaluated for impairment	168,203	179,887
Total loans and leases	168,356	180,040
Residential
Allowance for loan and lease losses:
Individually evaluated for impairment	677	705
Collectively evaluated for impairment	42,864	42,731
Total allowance for loan and lease losses	43,541	43,436	45,638	46,099
Loans and leases:
Individually evaluated for impairment	17,375	19,158
Collectively evaluated for impairment	3,847,134	3,777,301
Total loans and leases	3,864,509	3,796,459
Consumer
Allowance for loan and lease losses:
Collectively evaluated for impairment	27,456	28,388
Total allowance for loan and lease losses	27,456	28,388	27,923	28,385
Loans and leases:
Collectively evaluated for impairment	1,503,129	1,510,772
Total loans and leases	1,503,129	1,510,772
Unallocated
Allowance for loan and lease losses:
Collectively evaluated for impairment	8,016	6,733
Total allowance for loan and lease losses	$ 8,016	$ 6,733	$ 4,741	$ 3,805