Parent Company Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 28,791	$ 280,338	$ 336,372
Adjustments to reconcile net income to cash used in operating activities:
Share-based compensation expense	19,390	18,925	13,264
Loss on debt extinguishment	(793)	0	180
Deferred income tax (benefit) expense	3,962	5,899	28,807
Change in accrued expenses and other liabilities, net	21,204	6,512	(29,038)
Change in accrued interest receivable and other assets, net	(100,749)	74,532	59,234
Net cash provided by operating activities	250,980	411,032	320,215
Cash flows from investing activities:
Net cash provided by investing activities	2,471,898	(160,093)	(2,007,697)
Cash flows from financing activities:
Net change in short-term borrowings	(200,000)	(358,000)	548,000
Redemption of subordinated debentures	0	0	(171,153)
Repurchase and retirement of common stock	0	0	(18,067)
Proceeds from exercise of options	966	873	1,001
Net cash (used in) provided by financing activities	(2,887,654)	545,607	1,111,419
Net change in cash and cash equivalents	(164,776)	796,546	(576,063)
Cash and cash equivalents, beginning of year	1,101,249	304,703	880,766
Cash and cash equivalents, end of year	936,473	1,101,249	304,703
Corporation
Cash flows from operating activities:
Net income	30,852	283,743	339,889
Adjustments to reconcile net income to cash used in operating activities:
Share-based compensation expense	19,390	18,925	13,264
Equity in undistributed losses (earnings) of subsidiary	150,171	(172,104)	(238,992)
Loss on debt extinguishment	0	0	2,877
Deferred income tax (benefit) expense	(3,583)	230	(429)
Change in accrued expenses and other liabilities, net	2,331	2,985	377
Change in accrued interest receivable and other assets, net	(12,505)	(2,345)	(12,840)
Net cash provided by operating activities	186,656	131,434	104,146
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	(8,000)	8,000
Redemption of subordinated debentures	0	0	(36,153)
Cash dividends paid	(126,265)	(125,160)	(121,887)
Repurchase and retirement of common stock	0	0	(18,067)
Proceeds from exercise of options	966	873	1,001
Restricted stock surrendered and canceled	(6,373)	(8,918)	(6,384)
Net cash (used in) provided by financing activities	(131,672)	(141,205)	(173,490)
Net change in cash and cash equivalents	54,984	(9,771)	(69,344)
Cash and cash equivalents, beginning of year	17,712	27,483	96,827
Cash and cash equivalents, end of year	$ 72,696	$ 17,712	$ 27,483