Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 19,393,000	$ 18,751,000	$ 16,148,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	1,430,000	2,993,000	3,267,000
Depreciation and amortization	7,028,000	6,081,000	5,603,000
Stock-based compensation expense	1,753,000	2,380,000	1,803,000
Income on bank-owned life insurance, net	(701,000)	(747,000)	(553,000)
Net gains on life insurance	0	0	(163,000)
Net gains on sales of investments	(716,000)	(802,000)	(1,828,000)
Mortgage loans originated for sale	(19,820,000)	(28,873,000)	(23,673,000)
Proceeds from mortgage loans sold	21,641,000	29,614,000	24,827,000
Net gains on sales of loans	(460,000)	(601,000)	(492,000)
Net gains on sales of OREO	0	0	(154,000)
Changes in:
Decrease (increase) in other assets	6,026,000	(2,174,000)	64,000
Increase in other liabilities	2,357,000	701,000	874,000
Net cash provided by operating activities	37,931,000	27,323,000	25,723,000
Cash flows from investing activities:
Proceeds from sales of investment securities	133,736,000	4,800,000	25,115,000
Net (purchases) proceeds from FHLB capital stock	(3,121,000)	956,000	307,000
Proceeds from maturities, calls and pay-downs of investment securities	32,643,000	30,930,000	26,731,000
Purchase of investment securities	(187,158,000)	(118,255,000)	(108,962,000)
Net increase in loans	(247,032,000)	(163,426,000)	(188,738,000)
Additions to premises and equipment, net	(8,211,000)	(7,918,000)	(3,938,000)
Proceeds from OREO sales and payments	0	0	1,015,000
Proceeds from bank-owned life insurance	0	405,000	0
Purchase of bank-owned life insurance	0	0	(11,390,000)
Net cash used in investing activities	(279,143,000)	(252,508,000)	(259,860,000)
Cash flows from financing activities:
Net increase in deposits	172,441,000	250,773,000	249,602,000
Net increase (decrease) in borrowed funds	78,329,000	(43,000,000)	(5,229,000)
Repayment of subordinated debt	0	0	(10,825,000)
Proceeds from the issuance of subordinated debt	0	0	15,000,000
Cash dividends paid	(6,241,000)	(5,684,000)	(5,158,000)
Proceeds from issuance of common stock, net of expenses	1,590,000	21,183,000	1,448,000
Net settlement for employee taxes on restricted stock and options	(931,000)	(442,000)	0
Proceeds from stock option exercises	355,000	546,000	431,000
Tax benefit from stock-based compensation	0	789,000	217,000
Net cash provided by financing activities	245,543,000	224,165,000	245,486,000
Net increase (decrease) in cash and cash equivalents	4,331,000	(1,020,000)	11,349,000
Cash and cash equivalents, beginning of year	50,475,000	51,495,000	40,146,000
Cash and cash equivalents, end of year	54,806,000	50,475,000	51,495,000
Supplemental financial data:
Cash Paid For: Interest	7,295,000	5,536,000	5,467,000
Cash Paid For: Income taxes	10,459,000	10,868,000	7,594,000
Supplemental schedule of non-cash activity:
Net purchases (sales) of investment securities not yet settled	9,154,000	(301,000)	2,296,000
Bank owned life insurance proceeds not yet received	0	0	403,000
Capital expenditures incurred not yet paid	$ 0	$ 0	$ 525,000