Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Activities
Net Income (Loss) Attributable to Parent	$ 89,595	$ 89,352	$ 70,002
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and (accretion), net	4,882	699	1,281
Provision for (recovery of) credit losses	10,722	(1,250)	(2,310)
Depreciation of premises and equipment	5,790	5,003	5,087
Deferred income tax expense (benefit)	2,640	4,939	(1,244)
Net periodic employee benefit cost	723	622	471
Pension contributions	(450)	0	(1,509)
Unrealized and realized investment securities losses (gains)	801	(957)	90
Gain on Sale of Investments	(17,837)	0	0
Stock-based compensation expense	3,253	2,516	2,151
Excess tax benefit from stock-compensation expense	(165)	(461)	(506)
Increase in value of bank-owned life insurance	(4,424)	(3,766)	(3,090)
Loans originated for sale	(28,236)	(18,757)	(15,196)
Proceeds from the sale of loans originated for sale	28,909	20,917	13,993
Gain on sale of loans	(368)	(589)	(351)
Asset write down	0	297	491
Change in accrued interest receivable	(4,224)	855	(1,500)
Change in other assets	(13,790)	(1,959)	5,404
Change in other liabilities	11,974	7,587	4,308
Net Cash Provided by Operating Activities	89,795	105,048	77,572
Investing Activities
Net increase in loans	(3,911)	(30,146)	(95,284)
Purchases of securities available-for-sale	(461,430)	(209,588)	(130,876)
Proceeds from sales of available for sale securities	30,307	70,404	0
Proceeds from maturities and calls of available-for-sale securities	139,175	75,717	56,841
Purchases of securities held-to-maturity securities	0	0	(4,925)
Proceeds from maturities and calls of held-to-maturity securities	0	11,706	8,439
Payments to Acquire Other Investments	(2,295)	(11,100)	(35,350)
Proceeds from Sale of Other Investments	2,425	13,790	31,271
Proceeds from Sale and Maturity of Other Investments	17,837	0	0
Purchases of premises and equipment	(5,544)	(4,729)	(10,192)
Disposals of premises and equipment	483	598	3,884
Proceeds from Sale of Property Held-for-sale	540	2,285	0
Proceeds from bank-owned life insurance policies	2,019	2,423	425
Payments to Acquire Low Income Housing Tax Credits	(4,892)	(5,530)	(4,924)
Payments for (Proceeds from) Businesses and Interest in Affiliates	0	(24,661)	0
Net Cash Used in Investing Activities	(285,286)	(108,831)	(168,465)
Financing Activities
Net increase in noninterest-bearing deposits	371,903	26,727	32,097
Net increase in interest-bearing deposits	205,041	100,192	156,302
Net increase (decrease) in short-term borrowings	84,701	(50,656)	7,667
Repayment of long-term debt	(4,056)	0	(16,495)
Proceeds from sale of capital securities	0	0	495
Purchases of treasury stock	(36,481)	(19,431)	(20,271)
Proceeds from exercise of stock options	223	526	1,164
Other financing activities	(652)	(875)	0
Dividends paid	(36,673)	(35,547)	(29,583)
Net Cash Provided by Financing Activities	584,006	20,936	131,376
Increase in Cash and Cash Equivalents	388,515	17,153	40,483
Cash and cash equivalents at beginning of period	140,144	122,991	82,508
Cash and Cash Equivalents at End of Period	$ 528,659	$ 140,144	122,991
Farmers Deposit Bancorp, Inc. [Member]
Investing Activities
Payments to Acquire Businesses, Net of Cash Acquired			(20,691)
Poage Bankshares, Inc. [Member]
Investing Activities
Payments to Acquire Businesses, Net of Cash Acquired			$ 32,917