Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	RETAINED EARNINGS	RETAINED EARNINGS Cumulative Effect, Period of Adoption, Adjustment	ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME	TREASURYSTOCK	UNALLOCATED ESOP SHARES	COMMON STOCK ACQUIRED BY DEFERRED COMP PLANS	DEFERRED COMPENSATION PLANS
Beginning Balance at Dec. 31, 2021	$ 1,697,096		$ 832	$ 969,815	$ 814,533		$ 6,863	$ (79,603)	$ (15,344)	$ (3,984)	$ 3,984
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	83,191				83,191
Other comprehensive loss, net of tax	(118,662)						(118,662)
Cash dividends paid	(36,747)				(36,747)
Distributions from deferred comp plans	86			86						279	(279)
Purchases of treasury stock	(46,530)							(46,530)
Purchase of employee restricted shares to fund statutory tax withholding	(958)							(958)
Allocation of ESOP shares	2,205			582					1,623
Allocation of SAP shares	5,485			5,485
Allocation of stock options	99			99
Ending Balance at Jun. 30, 2022	1,585,265		832	976,067	860,977		(111,799)	(127,091)	(13,721)	(3,705)	3,705
Beginning Balance at Dec. 31, 2021	$ 1,697,096		832	969,815	814,533		6,863	(79,603)	(15,344)	(3,984)	3,984
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of adopting Accounting Standards Update ("ASU") No. 2022-02, net of tax	Accounting Standards Update 2022-02 [Member]
Ending Balance at Dec. 31, 2022	$ 1,597,703	$ 433	832	981,138	918,158	$ 433	(165,045)	(127,154)	(10,226)	(3,427)	3,427
Beginning Balance at Mar. 31, 2022	1,621,131		832	972,552	839,807		(67,946)	(109,581)	(14,533)	(3,844)	3,844
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	39,228				39,228
Other comprehensive loss, net of tax	(43,853)						(43,853)
Cash dividends paid	(18,058)				(18,058)
Distributions from deferred comp plans	41			41						139	(139)
Purchases of treasury stock	(17,505)							(17,505)
Purchase of employee restricted shares to fund statutory tax withholding	(5)							(5)
Allocation of ESOP shares	1,062			250					812
Allocation of SAP shares	3,174			3,174
Allocation of stock options	50			50
Ending Balance at Jun. 30, 2022	1,585,265		832	976,067	860,977		(111,799)	(127,091)	(13,721)	(3,705)	3,705
Beginning Balance at Dec. 31, 2022	1,597,703	$ 433	832	981,138	918,158	$ 433	(165,045)	(127,154)	(10,226)	(3,427)	3,427
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	72,539				72,539
Other comprehensive loss, net of tax	2,552						2,552
Cash dividends paid	(36,727)				(36,727)
Distributions from deferred comp plans	79			79						277	(277)
Purchase of employee restricted shares to fund statutory tax withholding	(1,671)							(1,671)
Stock option exercises	790			(217)				1,007
Allocation of ESOP shares	1,866			243					1,623
Allocation of SAP shares	4,830			4,830
Allocation of stock options	77			77
Ending Balance at Jun. 30, 2023	1,642,471		832	986,150	954,403		(162,493)	(127,818)	(8,603)	(3,150)	3,150
Beginning Balance at Mar. 31, 2023	1,640,080		832	984,089	940,533		(148,146)	(127,814)	(9,414)	(3,289)	3,289
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	32,003				32,003
Other comprehensive loss, net of tax	(14,347)						(14,347)
Cash dividends paid	(18,133)				(18,133)
Distributions from deferred comp plans	32			32						139	(139)
Purchase of employee restricted shares to fund statutory tax withholding	(4)							(4)
Allocation of ESOP shares	810			(1)					811
Allocation of SAP shares	1,997			1,997
Allocation of stock options	33			33
Ending Balance at Jun. 30, 2023	$ 1,642,471		$ 832	$ 986,150	$ 954,403		$ (162,493)	$ (127,818)	$ (8,603)	$ (3,150)	$ 3,150