Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2020	$ 1,741,117	$ 13,215	$ 233,120	$ 1,495,833	$ (1,051)
Balance (in shares) at Dec. 31, 2020		63,424,526
Net income per consolidated statements of income	147,365			147,365
Other comprehensive income (loss), net of tax	(31,509)				(31,509)
Cash dividends paid on common stock ($0.92 per share)	(58,085)			(58,085)
Shares withheld to pay taxes, long-term incentive plan	(1,379)	$ 28	(1,407)
Shares withheld to pay taxes, long-term incentive plan (in shares)		133,907
Repurchase and retirement of common stock	(61,799)	$ (398)	(61,401)
Repurchase and retirement of common stock (in shares)		(1,909,754)
Compensation expense, long-term incentive plan	5,601		5,601
Balance at Dec. 31, 2021	1,741,311	$ 12,845	175,913	1,585,113	(32,560)
Balance (in shares) at Dec. 31, 2021		61,648,679
Net income per consolidated statements of income	71,887			71,887
Other comprehensive income (loss), net of tax	(242,843)				(242,843)
Cash dividends paid on common stock ($0.92 per share)	(56,679)			(56,679)
Shares withheld to pay taxes, long-term incentive plan	(1,687)	$ 24	(1,711)
Shares withheld to pay taxes, long-term incentive plan (in shares)		118,398
Repurchase and retirement of common stock	(24,604)	$ (164)	(24,440)
Repurchase and retirement of common stock (in shares)		(789,391)
Compensation expense, long-term incentive plan	4,883		4,883
Balance at Dec. 31, 2022	$ 1,492,268	$ 12,705	154,645	1,600,321	(275,403)
Balance (in shares) at Dec. 31, 2022	60,977,686	60,977,686
Net income per consolidated statements of income	$ 165,489			165,489
Other comprehensive income (loss), net of tax	55,680				55,680
Cash dividends paid on common stock ($0.92 per share)	(56,653)			(56,653)
Shares withheld to pay taxes, long-term incentive plan	(1,092)	$ 20	(1,112)
Shares withheld to pay taxes, long-term incentive plan (in shares)		93,487
Compensation expense, long-term incentive plan	6,155		6,155
Balance at Dec. 31, 2023	$ 1,661,847	$ 12,725	$ 159,688	$ 1,709,157	$ (219,723)
Balance (in shares) at Dec. 31, 2023	61,071,173	61,071,173