CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2023
Cash flows from operating activities:
Net income	$ 163,355	$ 106,058	$ 97,856	$ 96,280	$ 402,580	$ 264,560
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization					28,731	31,245
Stock-based compensation					18,015	22,995
Provision for credit losses	19,171		75,024		119,631	202,294
Net accretion of discounts and amortization of premium on securities and borrowings					(6,028)	(2,143)
Amortization of other intangible assets	7,544		8,692		22,990	26,672
(Gains) losses on available for sale and held to maturity debt securities, net					(17)	12
Proceeds from sales of loans held for sale at fair value					139,507	155,863
(Gains) losses on sales of loans, net	(740)		3,644		(4,962)	1,142
Originations of loans held for sale					(124,768)	(148,294)
Gains on sales of assets, net					(78)	(3,747)
Loss on extinguishment of debt	0		0		922	0
Net change in:
Fair value of financial instruments hedged by derivative transactions					9,349	20,452
Trading debt securities					0	(23)
Lease right of use assets					7,434	8,421
Cash surrender value of bank owned life insurance					(15,121)	(13,167)
Accrued interest receivable					(2,920)	(4,633)
Other assets					113,953	(55,675)
Accrued expenses and other liabilities					(562,027)	(349,630)
Net cash provided by operating activities					147,191	156,344
Cash flows from investing activities:
Loans originated and purchased, net of principal collected					(582,053)	(408,268)
Equity securities:
Purchases					(11,687)	(8,295)
Sales and capital returns					3,989	1,146
Held to maturity debt securities:
Purchases					(278,690)	(60,585)
Maturities, calls and principal repayments					269,743	224,349
Available for sale debt securities:
Purchases					(990,956)	(1,410,651)
Maturities, calls and principal repayments					328,184	154,021
Death benefit proceeds from bank owned life insurance					7,012	6,852
Proceeds from sales of real estate property and equipment					2,277	3,702
Proceeds from sales of loans not originated for sale					11,899	230,666
Proceeds from sale of commercial premium finance lending division					0	98,060
Purchases of real estate property and equipment					(8,964)	(9,724)
Net cash used in investing activities					(1,249,246)	(1,178,727)
Cash flows from financing activities:
Net change in deposits					1,098,747	1,144,039
Net change in short-term borrowings					(21,666)	(859,566)
Proceeds from issuance of long-term borrowings, net					210,000	1,001,800
Repayments of long-term borrowings					(488,000)	(65,000)
Proceeds from issuance of preferred stock, net					0	144,654
Cash dividends paid to preferred shareholders					(21,547)	(16,141)
Cash dividends paid to common shareholders					(187,061)	(170,321)
Purchase of common shares related to stock compensation plan activity					(9,334)	(8,477)
Purchase of common shares to treasury					(16,358)	0
Common stock issued, net					17,698	78
Other, net					(109)	(3)
Net cash provided by financing activities					582,370	1,171,063
Net change in cash and cash equivalents					(519,685)	148,680
Cash and cash equivalents at beginning of year		1,890,125		$ 891,225	1,890,125	891,225
Cash and cash equivalents at end of period	1,370,440		$ 1,039,905		1,370,440	1,039,905	$ 891,225
Supplemental disclosures of cash flow information:
Interest on deposits and borrowings					1,164,037	1,348,751
Federal and state income taxes					64,590	82,712
Supplemental schedule of non-cash investing activities:
Transfer of loans to other real estate owned, net					832	7,172
Transfer of loans to loans held for sale, net	$ 3,900	$ 10,200			14,137	823,091	$ 10,000
Lease right of use assets obtained in exchange for operating lease liabilities					$ 25,791	$ 15,429