Parent Only Financial Information Parent Only Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities:
Net Income	$ 37,475	$ 36,279	$ 29,326
Shares Issued Under the Directors’ Stock Plan	258	205	233
Net Cash Provided By Operating Activities	43,944	41,976	37,827
Cash Flows from Investing Activities:
Proceeds from the Maturities and Calls of Securities Held-to-Maturity	41,607	58,978	49,244
Net Cash Used In Investing Activities	(192,231)	(227,770)	(148,566)
Cash Flows from Financing Activities:
Shares Issued for Stock Option Exercises, net	1,792	2,255	1,190
Shares Issued Under the Employee Stock Purchase Plan	493	505	496
Shares Issued for Dividend Reinvestment Plans	1,777	1,761	1,684
Purchase of Treasury Stock	(2,469)	(2,098)	(3,248)
Cash Dividends Paid	(15,206)	(14,389)	(13,599)
Net Cash Provided By Financing Activities	134,269	197,195	126,222
Net (Decrease) Increase in Cash and Cash Equivalents	(14,018)	11,401	15,483
Cash and Cash Equivalents at Beginning of Year	84,239	72,838	57,355
Cash and Cash Equivalents at End of Year	70,221	84,239	72,838
Interest on Deposits and Borrowings	20,843	12,212	6,957
Parent Company
Cash Flows from Operating Activities:
Net Income	37,475	36,279	29,326
Undistributed Net Income of Subsidiaries	(23,753)	(23,489)	(17,310)
Shares Issued Under the Directors’ Stock Plan	258	205	233
Changes in Other Assets and Other Liabilities	(1,236)	(918)	(1,179)
Net Cash Provided By Operating Activities	12,744	12,077	11,070
Cash Flows from Investing Activities:
Proceeds from the Maturities and Calls of Securities Held-to-Maturity	0	0	1,000
Net Cash Used In Investing Activities	0	0	1,000
Cash Flows from Financing Activities:
Shares Issued for Stock Option Exercises, net	1,792	2,255	1,190
Shares Issued Under the Employee Stock Purchase Plan	493	505	496
Shares Issued for Dividend Reinvestment Plans	1,777	1,761	1,684
Tax Benefit for Exercises of Stock Options	0	0	0
Purchase of Treasury Stock	(2,469)	(2,097)	(3,248)
Cash Dividends Paid	(15,206)	(14,389)	(13,599)
Net Cash Provided By Financing Activities	(13,613)	(11,965)	(13,477)
Net (Decrease) Increase in Cash and Cash Equivalents	(869)	112	(1,407)
Cash and Cash Equivalents at Beginning of Year	2,298	2,186	3,593
Cash and Cash Equivalents at End of Year	1,429	2,298	2,186
Interest on Deposits and Borrowings	$ 1,024	$ 976	$ 781