Consolidated Statements of Changes in Stockholder's Equity (Unaudited) - USD ($) $ in Thousands	Total	Restricted Stock	Effect of adopting ASU No. 2016-13 ("CECL")	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Restricted Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in Capital	Additional Paid-in Capital Restricted Stock	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Effect of adopting ASU No. 2016-13 ("CECL")	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive (Loss)	Accumulated Other Comprehensive (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock Held by the Employee Stock Ownership Plan	Common Stock Held by the Employee Stock Ownership Plan Cumulative Effect, Period of Adoption, Adjusted Balance	Stock Held by Rabbi Trust	Stock Held by Rabbi Trust Cumulative Effect, Period of Adoption, Adjusted Balance	Deferred Compensation Obligations	Deferred Compensation Obligations Cumulative Effect, Period of Adoption, Adjusted Balance
Balance at beginning of period at Dec. 31, 2021	$ 1,079,081		$ 6,212	$ 1,085,293	$ 1,246		$ 1,246	$ 667,906		$ 667,906	$ 765,133	$ 6,212	$ 771,345	$ (45,919)	$ (45,919)	$ (271,647)	$ (271,647)	$ (37,026)	$ (37,026)	$ (2,425)	$ (2,425)	$ 1,813	$ 1,813
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	64,282										64,282
Other comprehensive income (loss)	(155,230)													(155,230)
Issuance of common stock	102,741	$ 0			61	$ 1		102,680	$ (1)
Stock based compensation	5,787							5,787
Purchase of treasury stock	(71,766)															(71,766)
Exercise of stock options	(445)							(445)
Restricted stock forfeitures	0							1,448								(1,448)
Repurchase shares for taxes	(4,512)															(4,512)
Employee Stock Ownership Plan shares committed to be released	3,623							1,919										1,704
Funding of deferred compensation obligations	(128)																			(585)		457
Balance at end of year at Sep. 30, 2022	1,029,645				1,308			779,294			835,627			(201,149)		(349,373)		(35,322)		(3,010)		2,270
Balance at beginning of period at Jun. 30, 2022	1,074,284				1,308			776,542			814,708			(155,845)		(325,723)		(35,895)		(2,878)		2,067
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,919										20,919
Other comprehensive income (loss)	(45,304)													(45,304)
Stock based compensation	1,680							1,680
Purchase of treasury stock	(18,590)															(18,590)
Exercise of stock options	(253)							(253)
Restricted stock forfeitures	0							661								(661)
Repurchase shares for taxes	(4,399)															(4,399)
Employee Stock Ownership Plan shares committed to be released	1,237							664										573
Funding of deferred compensation obligations	71																			(132)		203
Balance at end of year at Sep. 30, 2022	1,029,645				1,308			779,294			835,627			(201,149)		(349,373)		(35,322)		(3,010)		2,270
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		$ 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)
Excise tax on net stock repurchases	(807)															(807)
Repurchase shares for taxes	(477)															(477)
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)
Excise tax on net stock repurchases	(110)															(110)
Repurchase shares for taxes	(344)															(344)
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