Parent Company Cash Flow Statement (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Financial Statements, Captions [Line Items]
Net income		$ 192,081	$ 239,502	$ 263,813
Adjustments to reconcile net income to net cash provided by operating activities
Deferred income tax (benefit) expense		(10,600)	2,738	(1,254)
Change in other liabilities		5,543	(20,614)	55,224
Net cash provided by operating activities		229,921	276,994	421,200
Cash flows used in investing activities
Net cash used in investing activities		(33,010)	(211,650)	(1,000,474)
Cash flows used in financing activities
Net cash used in financing activities		(201,351)	(193,947)	(1,308,477)
Payments for Repurchase of Common Stock		(30,986)	(188,910)	(139,946)
Cash received from stock option exercises		80	80	0
Proceeds from shares issued under direct stock purchase plan		3,254	2,662	2,359
Common dividends paid		(96,200)	(98,006)	(93,734)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect		(4,440)	(128,603)	(1,887,751)
Issuance Of Restricted Stock Awards, Net of Issuance Cost		815	1,142	1,084
Repayments of Subordinated Debt		(50,000)	0	0
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Investments in subsidiaries	[1]	2,967,786	2,922,698
Net income		192,081	239,502	263,813
Adjustments to reconcile net income to net cash provided by operating activities
Amortization		22	98	96
Deferred income tax (benefit) expense		(1)	24	28
Change in prepaid income taxes and other assets		179	2,107	(623)
Change in other liabilities		(2,560)	52	143
Equity in undistributed income of subsidiaries		13,745	17,656	59,131
Net cash provided by operating activities		175,976	224,127	204,326
Cash flows used in financing activities
Net cash used in financing activities		(174,667)	(285,316)	(246,468)
Cash and cash equivalents at beginning of year		108,788	169,977	212,119
Cash and cash equivalents at end of period		110,097	108,788	169,977
Cash	[2]	110,097	108,788
Payments for Repurchase of Common Stock		(30,986)	(188,910)	(139,946)
Repayments of Long-term Debt		0	0	(14,063)
Cash received from stock option exercises		80	80	0
Proceeds from shares issued under direct stock purchase plan		3,254	2,662	2,359
Common dividends paid		(96,200)	(98,006)	(93,734)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect		1,309	(61,189)	(42,142)
Issuance Of Restricted Stock Awards, Net of Issuance Cost		(815)	(1,142)	(1,084)
Subordinated Debt [Member] | Parent Company [Member]
Cash flows used in financing activities
Repayments of Subordinated Debt		$ 50,000	$ 0	$ 0

[1] Majority of balance eliminates in consolidation

[2] Entire balance eliminates in consolidation.