Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 338,741	$ 341,999
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,530	26,183
Provision for credit losses	40,255	42,151
Gain on other real estate and foreclosed assets	(1,826)	(375)
Deferred tax expense	4,640	3,266
Increase cash surrender value of life insurance contracts	(21,116)	(13,452)
(Gain) loss on disposal of assets	(1,365)	981
Net (increase) decrease in loans held for sale	1,614	(14,572)
Net amortization of securities premium/discount	10,211	14,233
Amortization of intangible assets	7,207	8,884
Stock-based compensation expense	17,171	18,677
Net change in derivative collateral liability	(31,172)	101,108
Net increase (decrease) in interest payable and other liabilities	(781)	26,642
Net (Increase) decrease in other assets	52,594	(143,211)
Other, net	(6,520)	(10,111)
Net cash provided by operating activities	434,183	402,403
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from maturities of securities available for sale	293,734	246,825
Purchases of securities available for sale	(542,759)	(40,047)
Proceeds from maturities of securities held to maturity	203,433	122,782
Purchases of securities held to maturity	0	(6,023)
Proceeds received upon termination of fair value hedge instruments	0	16,550
Payments made to terminate cash flow hedge instruments	(13,730)	(2,915)
Net increase in short-term investments	(168,149)	(493,889)
Net redemption (purchases) of Federal Home Loan Bank stock	122,528	(68,057)
Proceeds from sales of loans and leases	100,518	79,422
Net (increase) decrease in loans	307,662	(978,775)
Purchases of property and equipment	(7,500)	(24,572)
Proceeds from sales of other real estate and foreclosed assets	5,695	1,862
Other, net	(1,153)	(4,325)
Net cash provided by (used in) investing activities	300,279	(1,151,162)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase (decrease) in deposits	(707,154)	1,249,988
Net increase (decrease) in short-term borrowings	111,115	(445,343)
Dividends paid	(96,153)	(78,531)
Payroll tax remitted on net share settlement of equity awards	(6,880)	(3,321)
Proceeds from dividend reinvestment and stock purchase plans	3,095	2,858
Repurchase of common stock	(29,811)	0
Net cash provided by (used in) financing activities	(725,788)	725,651
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	8,674	(23,108)
CASH AND DUE FROM BANKS, BEGINNING	561,202	564,459
CASH AND DUE FROM BANKS, ENDING	569,876	541,351
SUPPLEMENTAL INFORMATION FOR NON-CASH INVESTING AND FINANCING ACTIVITIES
Assets acquired in settlement of loans	$ 28,010	$ 4,067