Parent Company Cash Flow Statement (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Net income		$ 239,502		$ 263,813	$ 120,992
Adjustments to reconcile net income to net cash provided by operating activities
Deferred income tax expense		2,738		(1,254)	3,090
Change in other liabilities		(20,614)		55,224	(58,503)
Net cash provided by operating activities		276,994		421,200	190,220
Cash flows used in investing activities
Net cash used in investing activities		(211,650)		(1,000,474)	(63,136)
Cash flows (used in) provided by financing activities
Net cash (used in) provided by financing activities		(193,947)		(1,308,477)	816,964
Payments for Repurchase of Common Stock		(188,910)		(139,946)	0
Repayments of Long-term Debt		0		(14,063)	(18,750)
Net payments from exercise of stock options					57
Cash received from stock option exercises		80		0
Proceeds from shares issued under direct stock purchase plan		2,662		2,359	2,023
Common dividends paid		(98,006)		(93,734)	(62,736)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect		(128,603)		(1,887,751)	944,048
Issuance Of Restricted Stock Awards, Net of Issuance Cost		1,142		1,084	1,249
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries	[1]	2,922,698		2,850,407
Net income		239,502		263,813	120,992
Adjustments to reconcile net income to net cash provided by operating activities
Amortization		98		96	137
Deferred income tax expense		24		28	12
Change in prepaid income taxes and other assets		2,107		(623)	(229)
Change in other liabilities		52		143	(1,873)
Equity in undistributed income of subsidiaries		17,656		59,131	46,571
Net cash provided by operating activities		224,127		204,326	72,468
Cash flows used in investing activities
Net cash acquired in business combinations		0		0	119,816
Net cash used in investing activities		0		0	119,816
Cash flows (used in) provided by financing activities
Net cash (used in) provided by financing activities		(285,316)		(246,468)	(80,769)
Cash and cash equivalents at beginning of year		169,977		212,119	100,604
Cash and cash equivalents at end of period		108,788		169,977	212,119
Cash		108,788	[2]	169,977
Payments for Repurchase of Common Stock		(188,910)		(139,946)	0
Repayments of Long-term Debt		0		(14,063)	(18,750)
Net payments from exercise of stock options		80
Cash received from stock option exercises					(57)
Proceeds from shares issued under direct stock purchase plan		2,662		2,359	2,023
Common dividends paid		(98,006)		(93,734)	(62,736)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect		(61,189)		(42,142)	111,515
Issuance Of Restricted Stock Awards, Net of Issuance Cost		$ (1,142)		$ (1,084)	$ (1,249)

[1] Majority of balance eliminates in consolidation

[2] Entire balance eliminates in consolidation.