Parent Company Cash Flow Statement (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Condensed Financial Statements, Captions [Line Items]
Net income		$ 263,813	$ 120,992	$ 121,167
Adjustments to reconcile net income to net cash provided by operating activities
Deferred income tax expense		(1,254)	3,090	(17,506)
Change in other liabilities		55,224	(58,503)	76,140
Net cash provided by operating activities		421,200	190,220	64,636
Cash flows used in investing activities
Net cash used in investing activities		(1,000,474)	(63,136)	(488,211)
Cash flows (used in) provided by financing activities
Net cash (used in) provided by financing activities		(1,308,477)	816,964	1,569,237
Payments for Repurchase of Common Stock		(139,946)	0	(95,091)
Repayments of Long-term Debt		(14,063)	(18,750)	(42,187)
Net payments from exercise of stock options		0	57
Cash received from stock option exercises				197
Proceeds from shares issued under the direct stock purchase plan		2,359	2,023	2,132
Common dividends paid		(93,734)	(62,736)	(60,840)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect		(1,887,751)	944,048	1,145,662
Issuance Of Restricted Stock Awards, Net of Issuance Cost		1,084	1,249	1,187
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries	[1]	2,850,407	2,952,089
Net income		263,813	120,992	121,167
Adjustments to reconcile net income to net cash provided by operating activities
Amortization		96	137	152
Deferred income tax expense		28	12	284
Change in prepaid income taxes and other assets		(623)	(229)	(475)
Change in other liabilities		143	(1,873)	(169)
Equity (deficit) in undistributed income of subsidiaries		59,131	46,571	(40,933)
Net cash provided by operating activities		204,326	72,468	161,892
Cash flows used in investing activities
Net cash acquired in business combinations		0	119,816	0
Net cash used in investing activities		0	119,816	0
Cash flows (used in) provided by financing activities
Net cash (used in) provided by financing activities		(246,468)	(80,769)	(196,976)
Cash and cash equivalents at beginning of year		212,119	100,604	135,688
Cash and cash equivalents at end of period		169,977	212,119	100,604
Cash	[2]	169,977	212,119
Payments for Repurchase of Common Stock		(139,946)	0	(95,091)
Repayments of Long-term Debt		(14,063)	(18,750)	(42,187)
Net payments from exercise of stock options			(57)
Cash received from stock option exercises				197
Proceeds from shares issued under the direct stock purchase plan		2,359	2,023	2,132
Common dividends paid		(93,734)	(62,736)	(60,840)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect		(42,142)	111,515	(35,084)
Issuance Of Restricted Stock Awards, Net of Issuance Cost		$ (1,084)	$ (1,249)	$ (1,187)

[1] Majority of balance eliminates in consolidation

[2] Entire balance eliminates in consolidation.