CONSOLIDATED STATEMENTS OF INCOME - USD ($)
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Interest income      
Loans, including fees $ 101,560,000 $ 87,002,000 $ 78,770,000
Securities      
Taxable 14,550,000 12,004,000 12,366,000
Tax exempt 12,000,000 11,970,000 11,862,000
Other interest income 217,000 134,000 97,000
Total interest income 128,327,000 111,110,000 103,095,000
Interest expense      
Deposits 4,169,000 3,678,000 3,678,000
Federal Home Loan Bank advances 4,418,000 3,387,000 3,572,000
Subordinated debentures 1,425,000 1,264,000 1,286,000
Other borrowings 714,000 56,000 71,000
Total interest expense 10,726,000 8,385,000 8,607,000
Net interest income 117,601,000 102,725,000 94,488,000
Provision for loan losses 1,705,000 1,625,000 1,500,000
Net interest income after provision for loan losses 115,896,000 101,100,000 92,988,000
Non-interest income      
Service charges on deposit accounts 21,006,000 22,039,000 20,698,000
Interchange income 11,116,000 9,239,000 7,590,000
Mortgage banking 10,044,000 8,355,000 6,754,000
Trust and investment product fees 4,866,000 4,947,000 4,712,000
Increase in cash surrender value of life insurance 1,513,000 1,236,000 1,298,000
Net realized gains on securities (includes $170, $386, $24 accumulated other comprehensive income (AOCI) reclassifications for realized net gains on available for sale securities 170,000 386,000 24,000
Gain/(Loss) on sale and write-down of OREO 268,000 68,000 (153,000)
Other income 3,629,000 4,002,000 2,084,000
Total non-interest income 52,612,000 50,272,000 43,007,000
Non-interest expense      
Salaries and employee benefits 64,327,000 57,741,000 54,132,000
Net occupancy 9,298,000 8,326,000 7,628,000
Equipment 12,696,000 11,360,000 10,337,000
Intangibles amortization 1,342,000 1,640,000 1,690,000
Telecommunications 1,647,000 1,775,000 1,747,000
Stationery printing and supplies 1,052,000 1,162,000 1,174,000
FDIC assessment 1,560,000 1,655,000 1,620,000
Marketing 3,390,000 3,193,000 3,187,000
Collection expense 910,000 1,173,000 1,330,000
Prepayment penalty on FHLB advance   2,364,000  
Acquisition related expenses 7,130,000 731,000 3,119,000
Consultant expense 549,000 1,106,000 1,400,000
Interchange expense 3,376,000 2,619,000 2,287,000
Other expenses 10,771,000 10,752,000 9,569,000
Total non-interest expense 118,048,000 105,597,000 99,220,000
Income before income tax 50,460,000 45,775,000 36,775,000
Income tax expense (includes $60, $135, and $8 income tax expense from AOCI reclassification items) 12,137,000 10,233,000 $ 7,779,000
Redemption of preferred stock $ 0    
Net income attributable to common shareholders   $ 35,542,000  
Net income per common share:      
Basic $ 1.66 $ 1.64 $ 1.40
Diluted 1.64 1.62 1.39
Dividend per share $ 0.61 $ 0.54 $ 0.42