Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 284,280	$ 286,981	$ 275,497
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for credit losses	54,036	28,021	(14,600)
Depreciation and amortization of premises and equipment	30,055	30,201	28,802
Net amortization of investment securities premiums	11,231	12,824	16,031
Investment securities losses (gains), net	733	27	(33,516)
Gain on sales of mortgage loans held for sale	(5,094)	(8,816)	(24,379)
Proceeds from sales of mortgage loans held for sale	363,406	455,607	1,050,943
Originations of mortgage loans held for sale	(366,206)	(418,287)	(978,446)
Intangible amortization	2,944	1,731	589
Amortization of issuance costs and discounts on long-term borrowings	750	724	1,846
Debt extinguishment costs	0	0	33,249
Stock-based compensation	12,540	14,000	8,402
Change in deferred federal income tax	24,666	(117,849)	(417)
Net change in accrued salaries and benefits	(5,868)	12,826	(1,226)
Change in life insurance cash surrender value	(27,664)	(95,702)	(93,986)
Other changes, net	(16,825)	392,503	69,602
Total adjustments	78,704	307,810	62,894
Net cash provided by operating activities	362,984	594,791	338,391
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from sales of AFS securities	213,424	196,411	359,137
Proceeds from principal repayments and maturities of AFS securities	149,211	583,444	469,393
Proceeds from principal repayments and maturities of HTM securities	59,685	109,759	117,958
Purchase of AFS securities	(79,053)	(845,744)	(1,309,470)
Purchase of HTM securities	0	(30,959)	(443,081)
Sale of Visa Shares	0	0	33,962
Net change in FRB and FHLB stock	5,781	(72,551)	34,494
Net change in loans	(1,100,816)	(1,407,289)	561,664
Net purchases of premises and equipment	(32,958)	(21,246)	(17,679)
Settlement of bank owned life insurance	2,264	3,474	3,881
Net cash paid for acquisition	0	(21,811)	(1,982)
Net change in tax credit investments	(26,753)	(29,071)	(18,363)
Net cash used in investing activities	(809,215)	(1,535,583)	(210,086)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net change in demand and savings deposits	(1,198,222)	(1,198,319)	1,315,139
Net change in time deposits and brokered deposits	2,086,307	(257,823)	(580,847)
Net (decrease) increase in other borrowings	(379,431)	1,629,870	(212,682)
Repayments of senior debt and subordinated debt	5,000	81,496	710,633
Net proceeds from issuance of common stock	3,160	7,876	7,437
Dividends paid	(115,738)	(116,009)	(112,028)
Acquisition of treasury stock	(77,056)	0	(43,909)
Net cash provided by (used in) financing activities	314,020	(15,901)	(337,523)
Net Increase in Cash and Cash Equivalents	(132,211)	(956,693)	(209,218)
Cash and Cash Equivalents at Beginning of Year	681,921	1,638,614	1,847,832
Cash and Cash Equivalents at End of Year	549,710	681,921	1,638,614
Cash paid during period for:
Interest	394,052	80,019	63,047
Income taxes	25,319	32,669	27,870
Supplemental schedule of certain noncash activities
Transfer of AFS securities to HTM securities	$ 0	$ 479,008	$ 376,165