Consolidated Statements Of Cash Flows	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Cash Flows From Operating Activities:
Net income	$ 41,573,000	$ 35,122,000	$ 30,880,000
Adjustments to reconcile net income to net cash provided by operating activities:
Provision (credit) for loan losses	(1,755,000)	4,854,000	3,480,000
Provision (credit) for deferred income taxes	(1,601,000)	1,114,000	1,233,000
Provision for losses on other real estate owned		725,000
Depreciation and amortization	4,068,000	3,604,000	3,219,000
Premium amortization on investment securities, net	1,714,000	3,045,000	4,002,000
Net (losses) gains on sales of securities	10,406,000	1,866,000	(1,868,000)
Net gain on sale of premises and equipment	(1,176,000)
Loss on debt extinguishment			1,756,000
Stock-based compensation expense	1,814,000	2,434,000	1,517,000
Accretion of cash surrender value on bank-owned life insurance	(2,134,000)	(1,568,000)	(932,000)
Pension expense (credit) less contribution	(319,000)	(118,000)	(1,536,000)
Increase (decrease) in accrued expenses and other liabilities	4,002,000	1,031,000	(3,313,000)
Other decreases (increases)	2,782,000	(4,937,000)	(2,849,000)
Net cash provided by operating activities	59,374,000	47,172,000	35,589,000
Proceeds from sales of investment securities:
Held-to-maturity		355,000	123,000
Available-for-sale	263,994,000	135,695,000	62,047,000
Proceeds from maturities and redemptions of investment securities:
Held-to-maturity	5,240,000	6,089,000	4,322,000
Available-for-sale	74,639,000	100,994,000	108,486,000
Purchases of investment securities:
Held-to-maturity	(3,059,000)	(2,606,000)	(1,403,000)
Available-for-sale	(397,174,000)	(144,885,000)	(267,329,000)
Proceeds from sales of loans held-for-sale	1,250,000		544,000
Proceeds from sale of real estate	6,793,000
Net increase in loans	(315,389,000)	(411,908,000)	(298,361,000)
Net increase in restricted stock	(3,372,000)	(5,551,000)	(3,328,000)
(Purchases of) proceeds from bank-owned life insurance, net	(18,561,000)	(25,000,000)	388,000
Purchases of premises and equipment, net	(5,687,000)	(8,891,000)	(7,250,000)
Net cash used in investing activities	(391,326,000)	(355,708,000)	(401,761,000)
Cash Flows From Financing Activities:
Net increase in deposits	262,975,000	213,280,000	324,042,000
Net increase (decrease) in short-term borrowings	107,782,000	74,129,000	(4,490,000)
Proceeds from long-term debt	39,680,000	71,635,000	43,500,000
Repayment of long-term debt	(101,450,000)	(27,050,000)	(31,756,000)
Proceeds from issuance of common stock, net	18,239,000	22,598,000	43,712,000
Proceeds from exercise of stock options	312,000	917,000	906,000
Repurchases of common stock	(1,541,000)
Shares withheld upon the vesting and conversion of RSUs	(774,000)	(527,000)	(370,000)
Cash dividends paid	(15,585,000)	(13,703,000)	(12,078,000)
Net cash provided by financing activities	309,638,000	341,279,000	363,466,000
Net (decrease) increase in cash and cash equivalents	(22,314,000)	32,743,000	(2,706,000)
Cash and cash equivalents, beginning of year	69,672,000	36,929,000	39,635,000
Cash and cash equivalents, end of period	47,358,000	69,672,000	36,929,000
Supplemental Cash Flow Disclosures:
Cash paid for interest	35,274,000	21,545,000	21,158,000
Cash paid for income taxes	2,490,000	12,838,000	9,006,000
Noncash investing and financing activities:
Cash dividends payable	4,456,000	3,798,000	$ 3,368,000
Additions to other real estate owned		$ 5,850,000
Loans transferred from portfolio to held-for-sale	$ 1,151,000