Parent Company Financial Statements (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 7,712	$ 7,721	$ 7,325	$ 7,306	$ 7,644	$ 7,708	$ 6,687	$ 6,305	$ 30,064	$ 28,344	$ 25,413
Adjustments to Reconcile Net Income to Net Cash from Operations
(Gain) on Securities, Net									(725)	(1,481)	(2,429)
Change in Other Assets									172	(10,119)	6,016
Change in Other Liabilities									(1,328)	9,917	(2,404)
Equity Based Compensation									963	627	329
Excess Tax Benefit from Restricted Share Grant									89	40	28
Net Cash from Operating Activities									31,267	36,468	41,674
CASH FLOWS FROM INVESTING ACTIVITIES
Net Cash from Investing Activities									(126,929)	(78,497)	(67,236)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from Issuance of Long-term Debt									75,000	20,321	47,000
Repayment of Long-term Debt									(44,135)	(43,117)	(49,379)
Issuance of Common Stock									49	50	20
Employee Stock Purchase Plan									447	(37)	(9)
Dividends Paid									(9,010)	(8,450)	(7,670)
Net Cash from Financing Activities									105,225	24,343	36,607
Net Change in Cash and Cash Equivalents									9,563	(17,686)	11,045
Cash and Cash Equivalents at Beginning of Year				42,446				60,132	42,446	60,132	49,087
Cash and Cash Equivalents at End of Year	52,009				42,446				52,009	42,446	60,132
Parent Company
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income									30,064	28,344	25,413
Adjustments to Reconcile Net Income to Net Cash from Operations
(Gain) on Securities, Net									0	0	(343)
Change in Other Assets									(5,331)	654	283
Change in Other Liabilities									1,226	275	(538)
Equity Based Compensation									963	627	329
Excess Tax Benefit from Restricted Share Grant									89	40	28
Equity in Excess Undistributed Income of Subsidiaries									(14,111)	(9,498)	(11,406)
Net Cash from Operating Activities									12,900	20,442	13,766
CASH FLOWS FROM INVESTING ACTIVITIES
Acquire Banking Entity									0	0	(2,135)
Net Cash from Investing Activities									0	0	(2,135)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from Issuance of Long-term Debt									0	0	10,000
Repayment of Long-term Debt									(4,000)	(3,000)	(33,750)
Issuance of Common Stock									49	50	20
Employee Stock Purchase Plan									447	(37)	(9)
Dividends Paid									(9,010)	(8,450)	(7,670)
Net Cash from Financing Activities									(12,514)	(11,437)	(31,409)
Net Change in Cash and Cash Equivalents									386	9,005	(19,778)
Cash and Cash Equivalents at Beginning of Year				$ 18,726				$ 9,721	18,726	9,721	29,499
Cash and Cash Equivalents at End of Year	$ 19,112				$ 18,726				$ 19,112	$ 18,726	$ 9,721