Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Activities
Net Income Available to Common Shareholders	$ 54,310	$ 52,128	$ 54,097
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and accretion	1,005	838	(4,589)
Provision for loan losses	3,006	4,395	6,988
Depreciation of premises and equipment	5,884	6,235	6,088
Deferred income tax expense	14,909	3,817	6,627
Net periodic employee benefit cost	298	515	836
Realized investment securities gains	(4,476)	(3,978)	(2,130)
Net investment securities impairment losses	0	465	0
Stock-based compensation expense	2,097	2,018	1,793
Excess Tax Benefit from Share-based Compensation, Operating Activities	(558)	0	0
Increase in value of bank-owned life insurance	(2,708)	(3,071)	(3,374)
Proceeds from life insurance	1,717	258	571
Originations of loans held for sale	(16,451)	(17,981)	(17,849)
Proceeds from loans held for sale	19,290	16,572	18,668
Gain on sale of loans	(516)	(374)	(367)
Gain on sale of insurance division	0	0	(11,084)
Asset write down	0	444	1,449
Change in accrued interest receivable	(815)	(976)	(375)
Change in other assets	1,277	(1,556)	(976)
Change in other liabilities	(426)	5,581	(8,478)
Net Cash Provided by Operating Activities	77,843	65,330	47,895
Investing Activities
Proceeds from sales of securities available-for-sale	5,776	30,850	389
Proceeds from maturities and calls of securities available-for-sale	86,276	78,720	55,726
Proceeds from maturities and calls of securities held-to-maturity	10,580	13,479	13,191
Purchases of securities available-for-sale	(187,031)	(196,150)	(175,271)
Purchases of securities held-to-maturity	0	0	(10,392)
Net increase in loans	(85,489)	(183,511)	(100,130)
Purchases of premises and equipment	(6,574)	(5,517)	(3,014)
Disposals of premises and equipment	3,057	836	141
Proceeds from sale of CityInsurance	0	0	15,250
Acquisition of American Founders Bank, Inc., including cash acquired of $561	0	0	20,030
Net Cash Used in Investing Activities	(173,405)	(261,293)	(184,080)
Financing Activities
Net (decrease) increase in noninterest-bearing deposits	(5,647)	200,984	52,230
Net increase (decrease) in interest-bearing deposits	89,644	(52,714)	18,544
Net increase in short-term borrowings	3,914	93,436	14,780
Issuance of common stock	28,408	6,864	0
Purchases of treasury stock	0	(10,018)	(7,055)
Proceeds from exercise of stock options	732	1,155	2,979
Proceeds from exercise of warrants	0	0	1,896
Dividends paid	(27,120)	(25,718)	(25,304)
Net Cash Provided by Financing Activities	89,931	213,989	58,070
(Decrease) Increase in Cash and Cash Equivalents	(5,631)	18,026	(78,115)
Cash and cash equivalents at beginning of period	88,139	70,113	148,228
Cash and Cash Equivalents at End of Period	$ 82,508	$ 88,139	$ 70,113