Parent Only Financial Information Parent Only Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows from Operating Activities:
Net Income	$ 36,279	$ 29,326	$ 26,534
Stock-Based Compensation Expense	356	351	287
Net Cash Provided By Operating Activities	41,976	37,827	34,695
Cash Flows from Investing Activities:
Proceeds from the Maturities and Calls of Securities Held-to-Maturity	58,978	49,244	56,461
Net Cash Used In Investing Activities	(227,770)	(148,566)	(157,789)
Cash Flows from Financing Activities:
Shares Issued for Stock Option Exercises, net	2,255	1,190	2,404
Shares Issued for Dividend Reinvestment Plans	1,761	1,684	1,743
Tax Benefit for Exercises of Stock Options	0	0	188
Purchase of Treasury Stock	(2,098)	(3,248)	(2,141)
Cash Dividends Paid	(14,389)	(13,599)	(13,092)
Net Cash Provided By Financing Activities	197,195	126,222	129,381
Net Increase (Decrease) in Cash and Cash Equivalents	11,401	15,483	6,287
Cash and Cash Equivalents at Beginning of Year	72,838	57,355	51,068
Cash and Cash Equivalents at End of Year	84,239	72,838	57,355
Parent Company
Cash Flows from Operating Activities:
Net Income	36,279	29,326	26,534
Undistributed Net Income of Subsidiaries	(23,489)	(17,310)	(15,283)
Stock-Based Compensation Expense	205	233	205
Changes in Other Assets and Other Liabilities	(918)	(1,179)	(899)
Net Cash Provided By Operating Activities	12,077	11,070	10,557
Cash Flows from Investing Activities:
Proceeds from the Maturities and Calls of Securities Held-to-Maturity	0	1,000	0
Net Cash Used In Investing Activities	0	1,000	0
Cash Flows from Financing Activities:
Shares Issued for Stock Option Exercises, net	2,255	1,190	2,404
Shares Issued Under the Employee Stock Purchase Plan	505	496	493
Shares Issued for Dividend Reinvestment Plans	1,761	1,684	1,743
Tax Benefit for Exercises of Stock Options	0	0	188
Purchase of Treasury Stock	(2,097)	(3,248)	(2,141)
Cash Dividends Paid	(14,389)	(13,599)	(13,092)
Net Cash Provided By Financing Activities	(11,965)	(13,477)	(10,405)
Net Increase (Decrease) in Cash and Cash Equivalents	112	(1,407)	152
Cash and Cash Equivalents at Beginning of Year	2,186	3,593	3,441
Cash and Cash Equivalents at End of Year	2,298	2,186	3,593
Interest on Deposits and Borrowings	$ 976	$ 781	$ 691