Loans and Leases - Schedule of Loans and Leases (Details) - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases $ 4,859,517 $ 4,837,735
Less: unearned income and deferred costs and fees (3,715) (3,796)
Total loans and leases, net of unearned income and deferred costs and fees 4,855,802 4,833,939
Originated    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 4,612,198 4,572,537
Less: unearned income and deferred costs and fees (3,715) (3,796)
Total loans and leases, net of unearned income and deferred costs and fees 4,608,483 4,568,741
Acquired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 247,319 265,198
Less: unearned income and deferred costs and fees 0 0
Total loans and leases, net of unearned income and deferred costs and fees 247,319 265,198
Commercial and industrial    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,043,789 1,077,635
Commercial and industrial | Agriculture    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 93,406 107,494
Commercial and industrial | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 950,383 970,141
Commercial and industrial | Originated    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,002,351 1,033,923
Commercial and industrial | Originated | Agriculture    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 93,406 107,494
Commercial and industrial | Originated | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 908,945 926,429
Commercial and industrial | Acquired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 41,438 43,712
Commercial and industrial | Acquired | Agriculture    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 0 0
Commercial and industrial | Acquired | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 41,438 43,712
Commercial real estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 2,401,976 2,340,661
Commercial real estate | Agriculture    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 180,698 170,229
Commercial real estate | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 2,034,240 2,004,763
Commercial real estate | Construction    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 187,038 165,669
Commercial real estate | Originated    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 2,235,213 2,161,569
Commercial real estate | Originated | Agriculture    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 180,479 170,005
Commercial real estate | Originated | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,869,057 1,827,279
Commercial real estate | Originated | Construction    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 185,677 164,285
Commercial real estate | Acquired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 166,763 179,092
Commercial real estate | Acquired | Agriculture    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 219 224
Commercial real estate | Acquired | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 165,183 177,484
Commercial real estate | Acquired | Construction    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,361 1,384
Residential real estate    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,324,206 1,333,894
Residential real estate | Home equity    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 222,713 229,608
Residential real estate | Mortgages    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,101,493 1,104,286
Residential real estate | Originated    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,285,893 1,292,261
Residential real estate | Originated | Home equity    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 204,058 208,459
Residential real estate | Originated | Mortgages    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 1,081,835 1,083,802
Residential real estate | Acquired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 38,313 41,633
Residential real estate | Acquired | Home equity    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 18,655 21,149
Residential real estate | Acquired | Mortgages    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 19,658 20,484
Consumer and other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 73,689 70,989
Consumer and other | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 59,686 58,326
Consumer and other | Indirect    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 14,003 12,663
Consumer and other | Originated    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 72,884 70,228
Consumer and other | Originated | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 58,881 57,565
Consumer and other | Originated | Indirect    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 14,003 12,663
Consumer and other | Acquired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 805 761
Consumer and other | Acquired | Other    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 805 761
Consumer and other | Acquired | Indirect    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 0 0
Leases    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 15,857 14,556
Leases | Originated    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases 15,857 14,556
Leases | Acquired    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Total loans and leases $ 0 $ 0