Allowance for Loan and Lease Losses (Details 2) - USD ($)
$ in Thousands
Sep. 30, 2016
Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total $ 4,092,940 $ 3,774,832
Commercial and industrial, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 1,009,039 941,133
Commercial real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 1,813,898 1,649,161
Residential real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 1,195,770 1,096,002
Consumer and other, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 58,375 59,644
Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 15,858 14,861
Covered Loans [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total 0 14,031
Originated Loans and Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 11,741 9,131
Collectively evaluated for impairment 3,664,191 3,304,427
Total 3,675,932 3,313,558
Originated Loans and Leases [Member] | Commercial and industrial, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 241 1,206
Collectively evaluated for impairment 924,127 855,117
Total 924,368 856,323
Originated Loans and Leases [Member] | Commercial real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 8,084 5,655
Collectively evaluated for impairment 1,544,030 1,351,567
Total 1,552,114 1,357,222
Originated Loans and Leases [Member] | Residential real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 3,416 2,270
Collectively evaluated for impairment 1,122,668 1,024,149
Total 1,126,084 1,026,419
Originated 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 57,508 58,733
Total 57,508 58,733
Originated Loans and Leases [Member] | Leases [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 0 0
Collectively evaluated for impairment 15,858 14,861
Total 15,858 14,861
Originated 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 5,387 7,050
Loans acquired with deteriorated credit quality 24,358 26,507
Collectively evaluated for impairment 387,263 427,717
Total 417,008 461,274
Acquired Loans and Leases [Member] | Commercial and industrial, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 9 647
Loans acquired with deteriorated credit quality 327 567
Collectively evaluated for impairment 84,335 83,596
Total 84,671 84,810
Acquired Loans and Leases [Member] | Commercial real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 4,006 5,226
Loans acquired with deteriorated credit quality 15,421 9,335
Collectively evaluated for impairment 242,357 277,378
Total 261,784 291,939
Acquired Loans and Leases [Member] | Residential real estate, total [Member]    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Individually evaluated for impairment 1,372 1,177
Loans acquired with deteriorated credit quality 8,610 3,801
Collectively evaluated for impairment 59,704 64,605
Total 69,686 69,583
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 867 911
Total 867 911
Acquired Loans and Leases [Member] | 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 0 12,804
Collectively evaluated for impairment 0 1,227
Total $ 0 $ 14,031