Parent Company Financial Information, Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows from Operating Activities [Abstract]
Net Income	$ 13,036	$ 12,000	$ 10,550	$ 9,941	$ 3,781	$ 8,581	$ 8,187	$ 7,821	$ 45,527	$ 28,370	$ 29,723
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities [Abstract]
Net Cash Provided by Operating Activities									57,774	39,944	34,812
Investing Activities [Abstract]
Net Cash Used in Investing Activities									(205,089)	(82,190)	(185,444)
Financing Activities [Abstract]
Stock Repurchased									(31,152)	0	0
Cash Dividends									(11,151)	(10,982)	(10,478)
Net Cash Provided by (Used by) Financing Activities									105,730	130,535	190,046
Increase (Decrease) in Cash and Cash Equivalents									(41,585)	88,289	39,414
Parent Company [Member]
Cash Flows from Operating Activities [Abstract]
Net Income									45,527	28,370	29,723
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities [Abstract]
Equity in Undistributed Net Earnings from Subsidiary									26,488	(5,575)	(17,043)
Net (Increase) Decrease in Other Assets									(125)	(11,822)	(124)
Net Increase (Decrease) in Liabilities									(942)	112	49
Net Cash Provided by Operating Activities									70,948	11,085	12,605
Investing Activities [Abstract]
Securities Sold or Matured									0	1	0
Payments for Business Acquisition									(28,642)	0	(2,207)
Payments for Investments in Subsidiaries									(10,503)	(2,953)	(2,586)
Net Cash Used in Investing Activities									(39,145)	(2,952)	(4,793)
Financing Activities [Abstract]
Stock Repurchased									(31,152)	0	0
Issuance of Common Stock									10,503	2,953	2,586
Cash Dividends									(11,151)	(10,982)	(10,478)
Net Cash Provided by (Used by) Financing Activities									(31,800)	(8,029)	(7,892)
Increase (Decrease) in Cash and Cash Equivalents									3	104	(80)
Cash and Cash Equivalents at Beginning of Year				$ 332				$ 228	332	228	308
Cash and Cash Equivalents at End of Year	$ 335				$ 332				$ 335	$ 332	$ 228