Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Net income	$ 239,502,000	$ 263,813,000	$ 120,992,000
Depreciation, Depletion and Amortization, Nonproduction	36,102,000	38,799,000	32,824,000
Change In Unamortized Net Loan Costs And Premiums	(1,856,000)	(7,119,000)	(24,785,000)
Accretion of acquired loans	(2,251,000)	175,000	(6,882,000)
Provision for credit losses	23,250,000	6,500,000	18,205,000
Deferred income tax expense	2,738,000	(1,254,000)	3,090,000
Equity Securities, FV-NI, Gain (Loss)	(1,180,000)	3,061,000	(554,000)
Gain (Loss) on Disposition of Property Plant Equipment	310,000	(584,000)	139,000
Sale and Leaseback Transaction, Gain (Loss), Net	193,000	578,000	578,000
Share-based Payment Arrangement, Noncash Expense	6,377,000	4,464,000	4,309,000
Life Insurance, Corporate or Bank Owned, Change in Value	(7,877,000)	(7,685,000)	(6,431,000)
Gain Realized on Life Insurance Policies	(2,291,000)	(1,291,000)	(258,000)
Operating Lease, Payments	(13,863,000)	(19,296,000)	(17,456,000)
Increase (Decrease) in Loans Held-for-sale	97,000	(452,000)	(1,679,000)
Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI	(1,099,000)	(168,000)	(882,000)
Increase (Decrease) in Loans Held-for-sale	(3,468,000)	21,424,000	31,746,000
Increase (Decrease) in Other Operating Assets	23,504,000	65,263,000	93,565,000
Change in other liabilities	(20,614,000)	55,224,000	(58,503,000)
Total adjustments	37,492,000	157,387,000	69,228,000
Net cash provided by operating activities	276,994,000	421,200,000	190,220,000
Proceeds from Sale of Debt and Equity Securities, FV-NI, Held-for-investment	0	31,000	1,164,000
Increase (Decrease) in Equity Securities, FV-NI	(742,000)	(1,524,000)	(2,171,000)
Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale	106,713,000	139,923,000	95,981,000
Payments to Acquire Debt Securities, Available-for-sale	0	(123,289,000)	(1,284,867,000)
Proceeds from maturities and principal repayments of securities held to maturity	140,888,000	166,712,000	263,106,000
Payments to Acquire Held-to-maturity Securities	0	(804,105,000)	(606,543,000)
Net (purchases) redemption of Federal Home Loan Bank stock	(38,339,000)	6,189,000	25,027,000
Investments in low income housing projects	(31,073,000)	(33,232,000)	(22,496,000)
Purchases of life insurance policies	(162,000)	(163,000)	(40,164,000)
Proceeds from Life Insurance Policy	5,531,000	3,160,000	576,000
Payments for (Proceeds from) Loans and Leases	(378,735,000)	(335,448,000)	744,981,000
Cash Acquired in Excess of Payments to Acquire Business	0	0	787,301,000
Payments to Acquire Property, Plant, and Equipment	(15,844,000)	(22,072,000)	(25,200,000)
Proceeds from Sale of Property, Plant, and Equipment	113,000	3,344,000	169,000
Net cash used in investing activities	(211,650,000)	(1,000,474,000)	(63,136,000)
Increase (Decrease) in Time Deposits	985,567,000	(334,381,000)	(235,577,000)
Increase (Decrease) in Other Deposits	(1,999,198,000)	(702,628,000)	1,719,398,000
Increase (Decrease) in Federal Funds Purchased and Securities Sold under Agreements to Repurchase, Net	1,105,000,000	(25,000,000)
Increase Decrease in Federal Home Loan Bank Advances Long Term	0	0	(586,088,000)
Repayments of Long-term Debt	0	(14,063,000)	(18,750,000)
Cash received from stock option exercises	80,000	0
Net payments from exercise of stock options			(57,000)
Issuance Of Restricted Stock Awards, Net of Issuance Cost	(1,142,000)	(1,084,000)	(1,249,000)
Proceeds from shares issued under direct stock purchase plan	2,662,000	2,359,000	2,023,000
Payments for Repurchase of Common Stock	(188,910,000)	(139,946,000)	0
Common dividends paid	(98,006,000)	(93,734,000)	(62,736,000)
Net cash (used in) provided by financing activities	(193,947,000)	(1,308,477,000)	816,964,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect, Total	(128,603,000)	(1,887,751,000)	944,048,000
Cash and cash equivalents at beginning of year	352,933,000	2,240,684,000	1,296,636,000
Cash and cash equivalents at end of period	224,330,000	352,933,000	2,240,684,000
Supplemental schedule of noncash investing and financing activities
Interest Paid, Excluding Capitalized Interest, Operating Activities	183,068,000	26,424,000	14,004,000
Income taxes	43,706,000	44,274,000	23,353,000
Capital commitment relating to Low Income Housing Project investments, noncash	31,891,000	17,643,000	33,691,000
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	7,916,000	14,789,000	7,768,000
In conjunction with the Company's acquisitions, assets were acquired and liabilities were assumed as follows
Common stock issued for acquisition	0	0	1,298,558,000
Fair value of assets acquired, net of cash acquired	0	0	5,574,209,000
Fair value of liabilities assumed	$ 0	$ 0	$ 5,062,952,000