Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Activities
Net Income Available to Common Shareholders	$ 88,080	$ 89,595	$ 89,352
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and (accretion), net	8,782	4,882	699
(Recovery of) provision for credit losses	(3,165)	10,722	(1,250)
Depreciation of premises and equipment	5,831	5,790	5,003
Deferred income tax expense	2,185	2,640	4,939
Net periodic employee benefit cost	569	723	622
Pension contributions	(1,000)	(450)	0
Unrealized and realized investment securities (gains) losses	(816)	801	(957)
Gain on Sale of Investments	0	(17,837)	0
Stock-based compensation expense	3,121	3,253	2,516
Excess tax benefit from stock-compensation expense	(579)	(165)	(461)
Increase in value of bank-owned life insurance	(3,895)	(4,424)	(3,766)
Loans originated for sale	(42,420)	(28,236)	(18,757)
Proceeds from the sale of loans originated for sale	42,769	28,909	20,917
Gain on sale of loans	(349)	(368)	(589)
Asset write down	0	0	297
Change in accrued interest receivable	166	(4,224)	855
Change in other assets	(8,737)	(13,790)	(1,959)
Change in other liabilities	11,731	11,974	7,587
Net Cash Provided by Operating Activities	102,273	89,795	105,048
Investing Activities
Net increase in loans	76,992	(3,911)	(30,146)
Payments to Acquire Debt Securities, Available-for-sale	560,689	461,430	209,588
Proceeds from Sale of Debt Securities, Available-for-sale	0	30,307	70,404
Proceeds from maturities and calls of available-for-sale securities	291,562	138,926	75,717
Proceeds from maturities and calls of held-to-maturity securities	0	0	11,706
Payments to Acquire Other Investments	(154)	(2,295)	(11,100)
Proceeds from Sale of Other Investments	4,813	2,674	13,790
Proceeds from Sale and Maturity of Other Investments	0	17,837	0
Purchases of premises and equipment	(3,323)	(5,544)	(4,729)
Disposals of premises and equipment	367	483	598
Proceeds from Sale of Property Held-for-sale	0	540	2,285
Proceeds from bank-owned life insurance policies	2,156	2,019	2,423
Payments to Acquire Low Income Housing Tax Credits	(2,891)	(4,892)	(5,530)
Payments for (Proceeds from) Businesses and Interest in Affiliates	0	0	(24,661)
Net Cash Used in Investing Activities	(191,167)	(285,286)	(108,831)
Financing Activities
Net increase in noninterest-bearing deposits	196,135	371,903	26,727
Net increase in interest-bearing deposits	77,178	205,041	100,192
Net increase (decrease) in short-term borrowings	16,502	84,701	(50,656)
Repayment of long-term debt	0	(4,056)	0
Purchases of treasury stock	(58,678)	(36,481)	(19,431)
Proceeds from exercise of stock options	691	223	526
Other financing activities	(824)	(652)	(875)
Dividends paid	(36,138)	(36,673)	(35,547)
Net Cash Provided by Financing Activities	194,866	584,006	20,936
Increase in Cash and Cash Equivalents	105,972	388,515	17,153
Cash and cash equivalents at beginning of period	528,659	140,144	122,991
Cash and Cash Equivalents at End of Period	$ 634,631	$ 528,659	$ 140,144