Consolidated Statements of Changes in Stockholder's Equity (Unaudited) - USD ($) $ in Thousands	Total	Restricted Stock	Common Stock	Common Stock Restricted Stock	Additional Paid-in Capital	Additional Paid-in Capital Restricted Stock	Retained Earnings	Accumulated Other Comprehensive (Loss)	Treasury Stock	Common Stock Held by the Employee Stock Ownership Plan	Stock Held by Rabbi Trust	Deferred Compensation Obligations
Balance at beginning of period at Dec. 31, 2022	$ 1,053,595		$ 1,309		$ 781,165		$ 857,518	$ (179,296)	$ (371,708)	$ (34,750)	$ (3,149)	$ 2,506
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,387						20,387
Other comprehensive income (loss)	13,125							13,125
Issuance of common stock allocated to restricted stock award grants		$ 9		$ 2		$ 7
Stock based compensation	3,873				3,873
Purchase of treasury stock	(69,321)								(69,321)
Exercise of stock options	(22)				(22)
Restricted stock forfeitures	0				225				(225)
Repurchase shares for taxes	(133)								(133)
Excise tax on net stock repurchases									(697)
Employee Stock Ownership Plan shares committed to be released	2,127				1,000					1,127
Funding of deferred compensation obligations	(155)										369	(524)
Balance at end of year at Jun. 30, 2023	1,022,788		1,311		786,248		877,905	(166,171)	(442,084)	(33,623)	(2,780)	1,982
Balance at beginning of period at Mar. 31, 2023	1,038,890		1,309		783,642		876,241	(167,858)	(419,678)	(34,190)	(2,668)	2,092
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	1,664						1,664
Other comprehensive income (loss)	1,687							1,687
Issuance of common stock allocated to restricted stock award grants		9		2		7
Stock based compensation	2,028				2,028
Purchase of treasury stock	(21,998)								(21,998)
Exercise of stock options	(33)				(33)
Restricted stock forfeitures	0				186				(186)
Excise tax on net stock repurchases	(222)								(222)
Employee Stock Ownership Plan shares committed to be released	985				418					567
Funding of deferred compensation obligations	(222)										(112)	(110)
Balance at end of year at Jun. 30, 2023	1,022,788		1,311		786,248		877,905	(166,171)	(442,084)	(33,623)	(2,780)	1,982
Balance at beginning of period at Dec. 31, 2023	1,040,335		1,312		791,450		893,604	(158,735)	(454,128)	(32,478)	(2,955)	2,265
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,385						3,385
Other comprehensive income (loss)	3,253							3,253
Issuance of common stock allocated to restricted stock award grants		$ 0		$ 2		$ (2)
Stock based compensation	4,270				4,270
Purchase of treasury stock	(5,894)								(5,894)
Exercise of stock options	(49)				(49)
Restricted stock forfeitures	0				30				(30)
Repurchase shares for taxes	(195)								(195)
Excise tax on net stock repurchases									(44)
Employee Stock Ownership Plan shares committed to be released	1,862				733					1,129
Funding of deferred compensation obligations	(189)										(151)	(38)
Balance at end of year at Jun. 30, 2024	1,046,734		1,314		796,432		896,989	(155,482)	(460,291)	(31,349)	(3,106)	2,227
Balance at beginning of period at Mar. 31, 2024	1,038,025		1,314		793,878		892,449	(160,837)	(455,948)	(31,914)	(3,041)	2,124
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	4,540						4,540
Other comprehensive income (loss)	5,355							5,355
Stock based compensation	2,241				2,241
Purchase of treasury stock	(4,242)								(4,242)
Restricted stock forfeitures	0				3				(3)
Repurchase shares for taxes	(56)								(56)
Excise tax on net stock repurchases	(42)								(42)
Employee Stock Ownership Plan shares committed to be released	875				310					565
Funding of deferred compensation obligations	38										(65)	103
Balance at end of year at Jun. 30, 2024	$ 1,046,734		$ 1,314		$ 796,432		$ 896,989	$ (155,482)	$ (460,291)	$ (31,349)	$ (3,106)	$ 2,227