Condensed Financial Information - Parent Company Only 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	$ 284,280	$ 286,981	$ 275,497
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities [Abstract]
Amortization of issuance costs and discounts on long-term borrowings	750	724	1,846
Stock-based compensation	12,540	14,000	8,402
Increase (Decrease) in Other Operating Liabilities	(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
Net cash paid for acquisition	0	(21,811)	(1,982)
Net cash used in investing activities	(809,215)	(1,535,583)	(210,086)
Cash Flows From Financing Activities:
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)
Parent
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 [Abstract]
Amortization of issuance costs and discounts on long-term borrowings	750	724	1,846
Stock-based compensation	12,540	14,000	8,402
Increase (Decrease) in Other Operating Assets	(37,591)	44,790	119,822
Equity in undistributed net (income) loss of subsidiaries	(13,073)	(120,213)	148,091
Write-off of unamortized costs on trust preferred securities	0	0	12,390
Increase (Decrease) in Other Operating Liabilities	(50,047)	(198,349)	78,716
Total adjustments	(87,421)	(259,048)	369,267
Net cash provided by operating activities	196,859	27,933	644,764
Cash Flows From Investing Activities
Net cash paid for acquisition	0	(21,811)	0
Net cash used in investing activities	0	(21,811)	0
Cash Flows From Financing Activities:
Repayments of long-term borrowings	(5,000)	(81,496)	(153,612)
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	(194,634)	(189,629)	(302,112)
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	2,225	(183,507)	342,652
Cash and Cash Equivalents at Beginning of Year	169,208	352,715	10,063
Cash and Cash Equivalents at End of Year	$ 171,433	$ 169,208	$ 352,715