Parent Company Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net income	$ 155,942	$ 28,791	$ 280,338
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation expense	21,717	19,390	18,925
Deferred income tax expense (benefit)	3,783	3,962	5,899
Net change in accrued expenses and other liabilities	(29,812)	21,204	6,512
Net change in accrued interest receivable and other assets	89,688	(100,749)	74,532
Net cash provided by operating activities	226,459	250,980	411,032
Cash flows from investing activities:
Net cash provided by investing activities	764,228	2,471,898	(160,093)
Cash flows from financing activities:
Net change in short-term borrowings	0	(200,000)	(358,000)
Repayment of subordinated debentures	(60,000)	0	0
Proceeds from exercise of stock options	908	966	873
Net cash (used in) provided by financing activities	(1,317,830)	(2,887,654)	545,607
Net change in cash and cash equivalents	(327,143)	(164,776)	796,546
Cash and cash equivalents, beginning of year	936,473	1,101,249	304,703
Cash and cash equivalents, end of year	609,330	936,473	1,101,249
Corporation
Cash flows from operating activities:
Net income	158,802	30,852	283,743
Adjustments to reconcile net income to net cash provided by operating activities:
Share-based compensation expense	21,717	19,390	18,925
Equity in undistributed losses (earnings) of subsidiary	40,691	150,171	(172,104)
Deferred income tax expense (benefit)	4,684	(3,583)	230
Net change in accrued expenses and other liabilities	(6,753)	2,331	2,985
Net change in accrued interest receivable and other assets	(18,563)	(12,505)	(2,345)
Net cash provided by operating activities	200,578	186,656	131,434
Cash flows from investing activities:
Net cash provided by investing activities	0	0	0
Cash flows from financing activities:
Net change in short-term borrowings	0	0	(8,000)
Repayment of subordinated debentures	(60,000)	0	0
Cash dividends paid	(127,108)	(126,265)	(125,160)
Proceeds from exercise of stock options	908	966	873
Restricted stock surrendered and canceled	(4,976)	(6,373)	(8,918)
Net cash (used in) provided by financing activities	(191,176)	(131,672)	(141,205)
Net change in cash and cash equivalents	9,402	54,984	(9,771)
Cash and cash equivalents, beginning of year	72,696	17,712	27,483
Cash and cash equivalents, end of year	$ 82,098	$ 72,696	$ 17,712