Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 460,815	$ 392,602	$ 524,089
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	32,301	34,720	31,582
Provision for credit losses	52,167	59,103	(28,399)
Gain on other real estate and foreclosed assets	(2,022)	(967)	(4,382)
Deferred tax expense (benefit)	4,299	13,986	(22,166)
Increase in cash surrender value of life insurance contracts	(27,315)	(17,671)	(7,010)
(Gain) loss on disposal or impairment of assets	(1,242)	(15,753)	259
Loss on sale of securities available for sale	0	65,380	87
Net (increase) decrease in loans held for sale	4,504	(24,589)	61,031
Net amortization of securities premium/discount	13,704	16,383	35,490
Amortization of intangible assets	9,413	11,556	14,033
Stock-based compensation expense	22,703	24,652	23,489
Net change in derivative collateral liability	(5,288)	58,326	64,867
Increase (decrease) in interest payable and other liabilities	(16,833)	48,714	6,838
(Increase) decrease in other assets	84,981	(160,890)	176,354
Other, net	(6,445)	(10,303)	(34,141)
Net cash provided by operating activities	625,742	495,249	842,021
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of securities available for sale	0	977,114	73,219
Proceeds from maturities of securities available for sale	454,188	813,214	502,628
Purchases of securities available for sale	(750,265)	(1,044,988)	(635,593)
Proceeds from maturities of securities held to maturity	238,899	163,266	147,879
Purchases of securities held to maturity	0	(6,023)	(884,427)
Proceeds received upon termination of fair value hedge instruments	0	19,275	90,601
Payments made to terminate cash flow hedge instruments	(13,730)	(2,915)	0
Net redemptions (purchases) of Federal Home Loan Bank stock	134,667	(68,057)	(12,095)
Net (increase) decrease in short-term investments	(312,633)	(303,022)	3,506,845
Proceeds from sales of loans and leases	119,166	115,119	30,652
Net (increase) decrease in loans	407,460	(968,237)	(2,088,836)
Purchases of life insurance contracts	0	0	(65,000)
Purchases of property and equipment	(10,237)	(25,025)	(29,145)
Proceeds from sales of property	6,144	33,130	62
Proceeds from sales of other real estate and foreclosed assets	1,795	3,575	14,081
Other, net	(698)	(1,637)	11,487
Net cash provided by (used in) investing activities	274,756	(295,211)	662,358
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in deposits	(197,208)	619,710	(1,395,548)
Net increase (decrease) in short-term borrowings	(515,814)	(716,442)	206,210
Repayments of long-term debt	0	0	(480)
Issuance of long-term debt, net of issuance costs	0	0	5,629
Dividends paid	(130,840)	(104,697)	(94,458)
Payroll tax remitted on net share settlement of equity awards	(9,358)	(5,681)	(7,386)
Other repurchases of common stock	(37,690)	0	(58,892)
Proceeds from exercise of stock options	0	0	227
Proceeds from dividend reinvestment and stock purchase plan	4,120	3,815	3,577
Net cash used in financing activities	(886,790)	(203,295)	(1,341,121)
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	13,708	(3,257)	163,258
CASH AND DUE FROM BANKS, BEGINNING	561,202	564,459	401,201
CASH AND DUE FROM BANKS, ENDING	574,910	561,202	564,459
SUPPLEMENTAL INFORMATION
Income taxes paid	89,635	103,190	135,193
Interest paid	635,770	487,681	80,076
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 28,491	$ 4,302	$ 596