Parent Company Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income (Loss) Attributable to Parent	$ 126,734	$ 148,351	$ 153,945
Share-based Payment Arrangement, Noncash Expense	8,010	7,199	8,021
Debt and Equity Securities, Unrealized Gain (Loss)	151	207	(1,218)
Increase (Decrease) in Other Operating Assets	(2,182)	4,467	(12,406)
Increase (Decrease) in Other Operating Liabilities	(6,982)	(4,814)	(7,939)
Net cash provided by operating activities	150,504	134,862	157,332
Payments to Acquire Available-for-sale Securities, Equity	2,195	9,165	0
Other investing activities, net	(31)	144	2,332
Net cash used in investing activities	64,157	(403,699)	(412,141)
Repayments of Long-term Debt	0	0	32,500
Payments Related to Tax Withholding for Share-based Compensation	2,844	2,761	2,403
Net cash (used in) provided by financing activities	(186,121)	239,385	103,515
Treasury Stock, Common [Member]
Payments for Repurchase of Equity	23,017	0	16,048
Parent Company
Net Income (Loss) Attributable to Parent	126,734	148,351	153,945
Undistributed Losses Of Subsidiaries	29,616	38,818	49,876
Compensation expense for issuance of treasury shares to directors	1,223	1,320	1,676
Share-based Payment Arrangement, Noncash Expense	6,787	5,879	6,345
Increase (Decrease) in Other Operating Assets	(828)	2,514	(8,249)
Increase (Decrease) in Other Operating Liabilities	(2,752)	4,896	(2,407)
Net cash provided by operating activities	103,355	119,321	116,714
Proceeds from Sale of Debt Securities	1,370	0	934
Payments to Acquire Available-for-sale Securities, Equity	(2,195)	(9,165)	0
Net cash used in investing activities	(856)	(9,021)	3,266
Payments of Dividends	68,951	76,604	74,306
Repayments of Long-term Debt	0	0	(32,500)
Cash Payment For Fractional Shares	0	2	6
Payments Related to Tax Withholding for Share-based Compensation	(2,844)	(2,761)	(2,403)
Net cash (used in) provided by financing activities	(94,812)	(79,367)	(125,263)
Increase (decrease) in cash and cash equivalents	7,687	30,933	(5,283)
Cash	$ 282,151	$ 274,464	$ 243,531	$ 248,814