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 Income (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	29,517						29,517
Other comprehensive income (loss)	(5,242)							(5,242)
Issuance of common stock allocated to restricted stock award grants		$ 9		$ 2		$ 7
Stock based compensation	6,156				6,156
Purchase of treasury stock	(78,295)								(78,295)
Exercise of stock options	(24)				(24)
Restricted stock forfeitures	0				469				(469)
Repurchase shares for taxes	(477)								(477)
Excise tax on net stock repurchases									(807)
Employee Stock Ownership Plan shares committed to be released	3,111				1,412					1,699
Funding of deferred compensation obligations	(112)										287	(399)
Balance at end of year at Sep. 30, 2023	1,007,431		1,311		789,185		887,035	(184,538)	(451,756)	(33,051)	(2,862)	2,107
Balance at beginning of period at Jun. 30, 2023	1,022,788		1,311		786,248		877,905	(166,171)	(442,084)	(33,623)	(2,780)	1,982
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,130						9,130
Other comprehensive income (loss)	(18,367)							(18,367)
Stock based compensation	2,283				2,283
Purchase of treasury stock	(8,974)								(8,974)
Exercise of stock options	(2)				(2)
Restricted stock forfeitures	0				244				(244)
Repurchase shares for taxes	(344)								(344)
Excise tax on net stock repurchases	(110)								(110)
Employee Stock Ownership Plan shares committed to be released	984				412					572
Funding of deferred compensation obligations	43										(82)	125
Balance at end of year at Sep. 30, 2023	1,007,431		1,311		789,185		887,035	(184,538)	(451,756)	(33,051)	(2,862)	2,107
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	9,570						9,570
Other comprehensive income (loss)	27,749							27,749
Issuance of common stock allocated to restricted stock award grants		$ 0		$ 2		$ (2)
Stock based compensation	5,511				5,511
Purchase of treasury stock	(5,894)								(5,894)
Exercise of stock options	(58)				(58)
Restricted stock forfeitures	0				73				(73)
Repurchase shares for taxes	(690)								(690)
Excise tax on net stock repurchases									(47)
Employee Stock Ownership Plan shares committed to be released	2,825				1,125					1,700
Funding of deferred compensation obligations	(151)										(228)	77
Balance at end of year at Sep. 30, 2024	1,079,150		1,314		798,099		903,174	(130,986)	(460,832)	(30,778)	(3,183)	2,342
Balance at beginning of period at Jun. 30, 2024	1,046,734		1,314		796,432		896,989	(155,482)	(460,291)	(31,349)	(3,106)	2,227
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	6,185						6,185
Other comprehensive income (loss)	24,496							24,496
Stock based compensation	1,241				1,241
Exercise of stock options	(9)				(9)
Restricted stock forfeitures	0				43				(43)
Repurchase shares for taxes	(495)								(495)
Excise tax on net stock repurchases	(3)								(3)
Employee Stock Ownership Plan shares committed to be released	963				392					571
Funding of deferred compensation obligations	38										(77)	115
Balance at end of year at Sep. 30, 2024	$ 1,079,150		$ 1,314		$ 798,099		$ 903,174	$ (130,986)	$ (460,832)	$ (30,778)	$ (3,183)	$ 2,342