Parent Company Financial Information, Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows from Operating Activities [Abstract]
Net Income	$ 14,644	$ 13,738	$ 14,105	$ 13,549	$ 13,036	$ 12,000	$ 10,550	$ 9,941	$ 56,036	$ 45,527	$ 28,370
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities [Abstract]
Net Cash Provided by Operating Activities									80,858	57,774	39,944
Investing Activities [Abstract]
Net Cash Used in Investing Activities									(135,630)	(205,089)	(82,190)
Financing Activities [Abstract]
Stock Repurchased									0	(31,152)	0
Cash Dividends									(11,221)	(11,151)	(10,982)
Net Cash Provided by Financing Activities									203,966	105,730	130,535
Net Change in Cash and Cash Equivalents									149,194	(41,585)	88,289
Parent Company [Member]
Cash Flows from Operating Activities [Abstract]
Net Income									56,036	45,527	28,370
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities [Abstract]
(Equity) Loss in Undistributed Net Earnings from Subsidiary									(44,571)	26,488	(5,575)
Net (Increase) in Other Assets									(160)	(125)	(11,822)
Net Increase (Decrease) in Liabilities									222	(942)	112
Net Cash Provided by Operating Activities									11,527	70,948	11,085
Investing Activities [Abstract]
Securities Sold or Matured									0	0	1
Payments for Business Acquisition									0	(28,642)	0
Payments for Investments in Subsidiaries									(6,273)	(10,503)	(2,953)
Net Cash Used in Investing Activities									(6,273)	(39,145)	(2,952)
Financing Activities [Abstract]
Stock Repurchased									0	(31,152)	0
Issuance of Common Stock									6,973	10,503	2,953
Cash Dividends									(11,221)	(11,151)	(10,982)
Net Cash Provided by Financing Activities									(4,248)	(31,800)	(8,029)
Net Change in Cash and Cash Equivalents									1,006	3	104
Cash and Cash Equivalents at Beginning of Year				$ 335				$ 332	335	332	228
Cash and Cash Equivalents at End of Year	$ 1,341				$ 335				$ 1,341	$ 335	$ 332