Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net income	$ 597,973	$ 579,150	$ 443,079
Adjustments to reconcile net income to net cash from operating activities:
Credit loss expense	46,171	3,000	63
Deferred tax expense (benefit)	(14,829)	(4,918)	7,784
Accretion of loan discounts	(17,724)	(12,921)	(12,890)
Securities premium amortization (discount accretion), net	63,893	97,400	119,242
Net (gain) loss on securities transactions	(66)	0	(69)
Depreciation and amortization	76,442	71,344	69,289
Net (gain) loss on sale/exchange/write-down of assets/foreclosed assets	750	109	(11,578)
Stock-based compensation	24,590	18,322	12,753
Net tax benefit from stock-based compensation	894	4,602	7,877
Earnings on life insurance policies	(2,944)	(2,096)	(2,462)
Net change in:
Trading account securities	(2,220)	(716)	(560)
Lease right-of-use assets	23,573	24,409	23,504
Accrued interest receivable and other assets	(232,665)	(116,243)	(46,560)
Accrued interest payable and other liabilities	(84,993)	61,140	38,821
Net cash provided by (used in) operating activities	478,845	722,582	648,293
Investing Activities:
Securities held to maturity: Purchases	(1,147,624)	(1,424,105)	0
Securities held to maturity: Maturities, calls and principal repayments	162,142	561,388	177,593
Securities available for sale:
Purchases	(19,124,336)	(22,178,248)	(24,217,841)
Sales	1,904,067	0	1,999,891
Maturities, calls and principal repayments	19,103,872	15,683,097	18,425,108
Proceeds from sale of loans	15,851	2,365	0
Net change in loans	(1,701,895)	(824,021)	1,145,924
Benefits received on life insurance policies	1,937	2,047	2,307
Proceeds from sales of premises and equipment	1,282	63	7,044
Purchases of premises and equipment	(158,630)	(102,501)	(65,850)
Proceeds from sales of repossessed properties	583	2,585	809
Net cash provided by (used in) investing activities	(942,751)	(8,277,330)	(2,525,015)
Financing Activities:
Net change in deposits	(2,033,628)	1,258,500	7,679,935
Net change in short-term borrowings	(570,903)	1,945,567	649,727
Principal payments on long-term borrowings	0	0	(13,403)
Proceeds from stock option exercises	9,299	16,659	54,417
Purchase of treasury stock	(42,720)	(4,391)	(3,864)
Cash dividends paid on preferred stock	(6,675)	(6,675)	(7,157)
Cash dividends paid on common stock	(232,323)	(209,780)	(188,786)
Net cash provided by (used in) financing activities	(2,876,950)	2,999,880	8,170,869
Net change in cash and cash equivalents	(3,340,856)	(4,554,868)	6,294,147
Cash and cash equivalents at beginning of year	12,028,132	16,583,000	10,288,853
Cash and cash equivalents at end of year	$ 8,687,276	$ 12,028,132	$ 16,583,000