Allowance for Loan and Lease Losses (Details 3) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total $ 3,395,676 $ 3,196,507
Commercial and industrial, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 864,070 765,730
Commercial real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 1,458,618 1,411,314
Residential real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 986,151 933,294
Consumer and other, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 55,267 54,738
Finance Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 12,251 5,563
Covered Loans [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 19,319 25,868
Orginated Loans and Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 10,366 22,156
Collectively Evaluated For Impairment 2,831,996 2,507,311
Total 2,842,362 2,529,467
Orginated Loans and Leases [Member] | Commercial and industrial, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 1,283 4,664
Collectively Evaluated For Impairment 765,753 632,563
Total 767,036 637,227
Orginated Loans and Leases [Member] | Commercial real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 7,675 16,269
Collectively Evaluated For Impairment 1,103,367 986,119
Total 1,111,042 1,002,388
Orginated Loans and Leases [Member] | Residential real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 1,408 1,223
Collectively Evaluated For Impairment 896,453 829,552
Total 897,861 830,775
Orginated Loans and Leases [Member] | Consumer and other, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 0 0
Collectively Evaluated For Impairment 54,172 53,514
Total 54,172 53,514
Orginated Loans and Leases [Member] | Finance Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 0 0
Collectively Evaluated For Impairment 12,251 5,563
Total 12,251 5,563
Orginated Loans and Leases [Member] | Covered Loans [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 0 0
Acquired Loans and Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 2,263 4,733
Loans Acquired With Deteriorated Credit Quality 34,410 46,809
Collectively Evaluated For Impairment 516,640 615,498
Total 553,314 667,040
Acquired Loans and Leases [Member] | Commercial and industrial, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 628 2,231
Loans Acquired With Deteriorated Credit Quality 995 2,558
Collectively Evaluated For Impairment 95,411 123,714
Total 97,034 128,503
Acquired Loans and Leases [Member] | Commercial real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 1,195 2,429
Loans Acquired With Deteriorated Credit Quality 11,640 10,263
Collectively Evaluated For Impairment 334,741 396,234
Total 347,576 408,926
Acquired Loans and Leases [Member] | Residential real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 440 73
Loans Acquired With Deteriorated Credit Quality 3,669 9,355
Collectively Evaluated For Impairment 84,181 93,091
Total 88,290 102,519
Acquired Loans and Leases [Member] | Consumer and other, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 0 0
Loans Acquired With Deteriorated Credit Quality 0 0
Collectively Evaluated For Impairment 1,095 1,224
Total 1,095 1,224
Acquired Loans and Leases [Member] | Finance Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 0 0
Acquired Loans and Leases [Member] | Covered Loans [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually Evaluated For Impairment 0 0
Loans Acquired With Deteriorated Credit Quality 18,106 24,633
Collectively Evaluated For Impairment 1,213 1,235
Total $ 19,319 $ 25,868