Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Cash Flows [Abstract]
Net income	$ 192,081,000	$ 239,502,000	$ 263,813,000
Depreciation, Depletion and Amortization, Nonproduction	40,889,000	36,102,000	38,799,000
Change In Unamortized Net Loan Costs And Premiums	(1,739,000)	(1,856,000)	(7,119,000)
Accretion of acquired loans	(538,000)	(2,251,000)	175,000
Provision for credit losses	36,250,000	23,250,000	6,500,000
Deferred income tax (benefit) expense	(10,600,000)	2,738,000	(1,254,000)
Equity Securities, FV-NI, Gain (Loss)	(423,000)	(1,180,000)	3,061,000
Gain (Loss) on Disposition of Property Plant Equipment	155,000	310,000	(584,000)
Sale and Leaseback Transaction, Gain (Loss), Net	0	193,000	578,000
Share-based Payment Arrangement, Noncash Expense	6,523,000	6,377,000	4,464,000
Life Insurance, Corporate or Bank Owned, Change in Value	(8,086,000)	(7,877,000)	(7,685,000)
Gain Realized on Life Insurance Policies	(457,000)	(2,291,000)	(1,291,000)
Operating Lease, Payments	(14,018,000)	(13,863,000)	(19,296,000)
Increase (Decrease) in Loans Held-for-sale	(20,000)	97,000	(452,000)
Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI	742,000	(1,099,000)	(168,000)
Increase (Decrease) in Loans Held-for-sale	(923,000)	(3,468,000)	21,424,000
Increase (Decrease) in Other Operating Assets	(15,498,000)	23,504,000	65,263,000
Change in other liabilities	5,543,000	(20,614,000)	55,224,000
Total adjustments	37,840,000	37,492,000	157,387,000
Net cash provided by operating activities	229,921,000	276,994,000	421,200,000
Proceeds from Sale of Debt and Equity Securities, FV-NI, Held-for-investment	0	0	31,000
Increase (Decrease) in Equity Securities, FV-NI	(1,058,000)	(742,000)	(1,524,000)
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale	235,144,000	106,713,000	139,923,000
Payments to Acquire Debt Securities, Available-for-sale	(129,379,000)	0	(123,289,000)
Proceeds from maturities and principal repayments of securities held to maturity	138,399,000	140,888,000	166,712,000
Payments to Acquire Held-to-maturity Securities	0	0	(804,105,000)
Net redemption (purchases) of Federal Home Loan Bank stock	11,984,000	(38,339,000)	6,189,000
Investments in low-income housing projects	(33,053,000)	(31,073,000)	(33,232,000)
Purchases of life insurance policies	(114,000)	(162,000)	(163,000)
Proceeds from Life Insurance Policy	1,929,000	5,531,000	3,160,000
Payments for (Proceeds from) Loans and Leases	(236,519,000)	(378,735,000)	(335,448,000)
Payments to Acquire Property, Plant, and Equipment	(20,435,000)	(15,844,000)	(22,072,000)
Proceeds from Sale of Property, Plant, and Equipment	92,000	113,000	3,344,000
Net cash used in investing activities	(33,010,000)	(211,650,000)	(1,000,474,000)
Increase (Decrease) in Time Deposits	565,752,000	985,567,000	(334,381,000)
Increase (Decrease) in Other Deposits	(125,436,000)	(1,999,198,000)	(702,628,000)
Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net	(467,000,000)	1,105,000,000	(25,000,000)
Cash received from stock option exercises	80,000	80,000	0
Repayments of Subordinated Debt	(50,000,000)	0	0
Issuance Of Restricted Stock Awards, Net of Issuance Cost	(815,000)	(1,142,000)	(1,084,000)
Proceeds from shares issued under direct stock purchase plan	3,254,000	2,662,000	2,359,000
Payments for Repurchase of Common Stock	(30,986,000)	(188,910,000)	(139,946,000)
Common dividends paid	(96,200,000)	(98,006,000)	(93,734,000)
Net cash used in financing activities	(201,351,000)	(193,947,000)	(1,308,477,000)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	(4,440,000)	(128,603,000)	(1,887,751,000)
Cash and cash equivalents at beginning of year	224,330,000	352,933,000	2,240,684,000
Cash and cash equivalents at end of period	219,890,000	224,330,000	352,933,000
Supplemental schedule of noncash investing and financing activities
Interest Paid, Excluding Capitalized Interest, Operating Activities	291,692,000	183,068,000	26,424,000
Income taxes	51,079,000	43,706,000	44,274,000
Capital commitment relating to Low Income Housing Project investments, noncash	46,070,000	31,891,000	17,643,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	12,602,000	7,916,000	14,789,000
In conjunction with the Company's acquisitions, assets were acquired and liabilities were assumed as follows
Repayments of Other Long-Term Debt	$ 0	$ 0	$ 14,063,000