Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities
Net Income Available to Common Shareholders	$ 89,352	$ 70,002	$ 54,310
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and accretion, net	699	1,281	1,005
(Recovery of) provision for loan losses	(1,250)	(2,310)	3,006
Depreciation of premises and equipment	5,003	5,087	5,884
Deferred income tax expense (benefit)	4,939	(1,244)	14,909
Net periodic employee benefit cost	622	471	298
Pension contributions	0	(1,509)	0
Unrealized and realized investment securities (gains) losses	(957)	90	(4,476)
Stock-based compensation expense	2,516	2,151	2,097
Excess tax benefit from stock-compensation expense	(461)	(506)	(558)
Increase in value of bank-owned life insurance	(3,766)	(3,090)	(2,708)
Loans originated for sale	(18,757)	(15,196)	(16,451)
Proceeds from the sale of loans originated for sale	20,917	13,993	19,290
Gain on sale of loans	(589)	(351)	(516)
Asset write down	297	491	0
Change in accrued interest receivable	855	(1,500)	(815)
Change in other assets	(7,489)	480	(2,102)
Change in other liabilities	6,712	4,308	2,953
Net Cash Provided by Operating Activities	98,643	72,648	76,126
Investing Activities
Net increase in loans	(30,146)	(95,284)	(85,489)
Purchases of securities available-for-sale	(209,588)	(130,876)	(159,317)
Proceeds from sales of available for sale securities	70,404	0	5,776
Proceeds from maturities and calls of available-for-sale securities	75,717	56,841	58,358
Purchases of securities held-to-maturity securities	0	(4,925)	0
Proceeds from maturities and calls of held-to-maturity securities	11,706	8,439	10,580
Payments to Acquire Other Investments	(11,100)	(35,350)	(27,714)
Proceeds from Sale of Other Investments	13,790	31,271	27,918
Purchases of premises and equipment	(4,729)	(10,192)	(6,574)
Disposals of premises and equipment	598	3,884	3,057
Proceeds from Sale of Property Held-for-sale	2,285	0	0
Proceeds from bank-owned life insurance policies	2,423	425	1,717
Payments for (Proceeds from) Businesses and Interest in Affiliates	(24,661)	0	0
Net Cash Used in Investing Activities	(103,301)	(163,541)	(171,688)
Financing Activities
Net increase (decrease) in noninterest-bearing deposits	26,727	32,097	(5,647)
Net increase (decrease) in interest-bearing deposits	100,192	156,302	89,644
Net (decrease) increase in short-term borrowings	(50,656)	7,667	3,914
Repayment of long-term debt	0	(16,495)	0
Proceeds from sale of capital securities	0	495	0
Issuance of common stock	0	0	28,408
Purchases of treasury stock	(19,431)	(20,271)	0
Proceeds from exercise of stock options	526	1,164	732
Dividends paid	(35,547)	(29,583)	(27,120)
Net Cash Provided by Financing Activities	21,811	131,376	89,931
Increase (Decrease) in Cash and Cash Equivalents	17,153	40,483	(5,631)
Cash and cash equivalents at beginning of period	122,991	82,508	88,139
Cash and Cash Equivalents at End of Period	$ 140,144	122,991	$ 82,508
Farmers Deposit Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		(20,691)
Poage Bankshares, Inc. [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 32,917