Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
INTEREST INCOME
Loans, leases and fees	$ 193,143,000	$ 172,342,000	$ 149,777,000
Federal funds sold and interest-bearing deposits with banks	1,559,000	880,000	569,000
Taxable investment securities and other	16,710,000	14,987,000	11,163,000
Tax-exempt investment securities	1,709,000	1,995,000	1,787,000
TOTAL INTEREST INCOME	213,121,000	190,204,000	163,296,000
INTEREST EXPENSE
Deposits	30,620,000	16,600,000	10,512,000
Federal funds purchased and securities sold under agreements to repurchase	471,000	198,000	69,000
Other borrowings	8,471,000	8,168,000	7,066,000
TOTAL INTEREST EXPENSE	39,562,000	24,966,000	17,647,000
NET INTEREST INCOME	173,559,000	165,238,000	145,649,000
Provision for loan and lease losses	4,413,000	6,090,000	4,223,000
NET INTEREST INCOME AFTER PROVISION FOR LOAN AND LEASE LOSSES	169,146,000	159,148,000	141,426,000
NONINTEREST INCOME
Service charges on deposit accounts	10,584,000	10,740,000	10,157,000
Commissions and fees	5,542,000	4,858,000	4,349,000
Income on bank owned life insurance	3,256,000	2,354,000	2,562,000
Loss on equity securities	(583,000)	0	0
Gains on sales of loans	1,329,000	1,836,000	2,123,000
Gain on sales and calls of investment securities, net	0	2,524,000	370,000
Other income	2,182,000	3,123,000	1,769,000
TOTAL NONINTEREST INCOME	22,310,000	25,435,000	21,330,000
NONINTEREST EXPENSE
Salaries and employee benefits	68,595,000	61,166,000	56,107,000
Net occupancy expense	10,155,000	10,243,000	9,935,000
Furniture and equipment	8,297,000	8,269,000	8,017,000
FDIC insurance expense	1,608,000	1,577,000	2,248,000
Stationery, supplies and postage	1,625,000	1,797,000	1,727,000
Marketing expense	1,437,000	1,675,000	1,672,000
Data processing expense	3,609,000	1,993,000	1,891,000
Telecommunications expense	1,769,000	1,607,000	1,631,000
ATM and debit card expense	2,195,000	2,051,000	1,582,000
Core deposit intangible amortization	594,000	654,000	734,000
Other real estate and repossessed asset expense	158,000	181,000	116,000
Long-term debt prepayment fee	0	2,828,000	0
Merger related expenses	464,000	0	4,103,000
Other expenses	10,661,000	10,493,000	10,154,000
TOTAL NONINTEREST EXPENSE	111,167,000	104,534,000	99,917,000
Income before provision for income taxes	80,289,000	80,049,000	62,839,000
Provision for income taxes	16,888,000	27,469,000	21,321,000
NET INCOME	$ 63,401,000	$ 52,580,000	$ 41,518,000
PER SHARE OF COMMON STOCK:
Basic earnings (usd per share)	$ 1.32	$ 1.10	$ 0.96
Diluted earnings (usd per share)	1.32	1.09	0.95
Cash dividends (usd per share)	$ 0.45	$ 0.4	$ 0.37