Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities
Net income	$ 38,802,000	$ 36,340,000	$ 21,485,000
Adjustments to reconcile net income to net cash provided by operating activities
Provision for loan losses	3,571,000	2,393,000	2,771,000
Depreciation and amortization of premises and equipment	3,448,000	2,912,000	3,560,000
Amortization of premiums on investments, net	195,000	40,000	172,000
Amortization of FDIC indemnification asset, net	2,377,000	2,181,000	3,517,000
Amortization of intangible assets	997,000	1,039,000	1,056,000
Goodwill impairment		1,492,000
Accretion on acquired loans	(3,231,000)	(6,391,000)	(5,417,000)
Equity-based compensation expense	1,481,000	1,158,000	790,000
Issuance of common stock to 401(k) plan	411,000	352,000	415,000
Gain on sale of premises and equipment, net	(75,000)	(25,000)	(1,000)
Provision expense and loss on sale of other real estate owned	1,253,000	1,313,000	791,000
Loss on sale of securities	43,000	618,000	661,000
Writedowns of property, plant & equipment	380,000	1,007,000	677,000
Loss on extinguishment of debt		1,096,000
Decrease in other operating activities	7,003,000	3,974,000	5,893,000
Net cash provided by operating activities	56,655,000	49,499,000	36,370,000
Investing activities
Proceeds from sale of securities available for sale	13,898,000	8,937,000	13,664,000
Proceeds from maturities, prepayments, and calls of securities available for sale	32,863,000	68,765,000	37,155,000
Proceeds from maturities and calls of securities held to maturity	25,000,000		21,840,000
Payments to acquire securities available for sale	(8,255,000)	(67,355,000)	(49,406,000)
Proceeds from repayments loans, net	85,233,000	39,512,000	37,455,000
Proceeds from bank owned life insurance		458,000	2,639,000
Payments for (redemption of) FHLB stock, net	129,000	(2,122,000)	694,000
Cash proceeds from mergers, acquisitions, and divestitures, net	25,863,000	10,000
(Payments to) proceeds from the FDIC	(152,000)	(151,000)	1,689,000
Proceeds from sale of premises and equipment	1,955,000	955,000	57,000
Payments to acquire premises and equipment	(8,411,000)	(2,551,000)	(2,354,000)
Proceeds from sale of other real estate owned	3,254,000	2,940,000	4,363,000
Net cash provided by investing activities	171,377,000	49,398,000	67,796,000
Financing activities
Increase in noninterest-bearing deposits, net	12,604,000	5,407,000	26,438,000
(Decrease) increase in interest-bearing deposits, net	(41,445,000)	(79,548,000)	62,115,000
Repayments of securities sold under agreements to repurchase, net	(27,769,000)	(716,000)	(67,919,000)
Repayments of FHLB and other borrowings, net		(50,000,000)	(30,708,000)
Proceeds from stock options exercised	136,000	384,000	378,000
Payments for repurchase of common stock	(16,362,000)	(34,412,000)	(1,263,000)
Payments of common stock dividends	(15,060,000)	(21,090,000)	(11,563,000)
Net cash used in financing activities	(87,896,000)	(179,975,000)	(22,522,000)
Net increase (decrease) in cash and cash equivalents	140,136,000	(81,078,000)	81,644,000
Cash and cash equivalents at beginning of period	76,873,000	157,951,000	76,307,000
Cash and cash equivalents at end of period	217,009,000	76,873,000	157,951,000
Supplemental disclosure -- cash flow information
Cash paid for interest	5,661,000	7,935,000	8,267,000
Cash paid for income taxes	8,057,000	7,610,000	15,852,000
Supplemental transactions -- non-cash items
Transfer of loans to other real estate	3,160,000	5,686,000	2,283,000
Loans originated to finance other real estate	484,000	164,000
Increase (decrease) in accumulated other comprehensive loss	77,000	589,000	(1,171,000)
Non-cash sales price related to divestitures		1,603,000
Fair value of assets acquired	556,005,000
Fair value of liabilities assumed	506,179,000
Net assets acquired	49,826,000
Common stock issued in acquisition	$ 86,631,000