Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net income	$ 67,374	$ 66,741
Adjustments to reconcile net income to net cash provided by operating activities:
(Accretion) and amortization, net	2,911	521
Provision for (recovery of) credit losses	10,248	(1,175)
Depreciation of premises and equipment	4,285	3,736
Deferred income tax expense	1,035	2,906
Net periodic employee benefit cost	542	579
Unrealized and realized investment securities losses (gains), net	1,642	(42)
Stock-compensation expense	2,455	1,901
Excess tax benefit from stock-compensation expense	(160)	(461)
Increase in value of bank-owned life insurance	(3,611)	(2,910)
Loans originated for sale	(19,345)	(14,229)
Proceeds from the sale of loans originated for sale	19,790	15,192
Gain on sale of loans	(277)	(421)
Payments for other operating activities	(450)	0
Change in accrued interest receivable	(5,058)	(505)
Change in other assets	(14,550)	(1,585)
Change in other liabilities	13,398	6,106
Net Cash Provided by Operating Activities	80,229	76,354
Investing Activities
Net (increase) decrease in loans	(45,316)	5,332
Purchases	(393,932)	(170,396)
Proceeds from sales	28,548	70,241
Proceeds from maturities and calls	96,021	55,237
Proceeds from maturities and calls	0	9,554
Other investments: Purchases	(2,173)	(10,366)
Other investments: Proceeds from sales	2,386	12,555
Purchases of premises and equipment	(4,351)	(3,515)
Proceeds from bank-owned life insurance policies	1,940	2,211
Sale of Virginia Beach branch, net	0	(24,661)
Other investing activities	(233)	(4,522)
Net Cash Used in Investing Activities	(317,110)	(58,330)
Financing Activities
Net increase in non-interest-bearing deposits	256,223	17,188
Net increase in interest-bearing deposits	88,425	63,099
Net increase (decrease) in short-term borrowings	68,611	(59,289)
Repayment of long-term debt	(4,124)	0
Purchases of treasury stock	(31,600)	(19,431)
Proceeds from exercise of stock options	223	526
Dividends paid	(27,651)	(26,257)
Other financing activities	(652)	(657)
Net Cash Provided by (Used in) Financing Activities	349,455	(24,821)
Increase (Decrease) in Cash and Cash Equivalents	112,574	(6,797)
Cash and cash equivalents at beginning of period	140,144	122,991
Cash and Cash Equivalents at End of Period	252,718	116,194
Supplemental Cash Flow Information [Abstract]
Cash paid for interest	20,491	27,884
Cash paid for income taxes	$ 21,975	$ 12,500