CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands		Total	Common Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Accumulated Other Comprehensive Loss Member	Treasury Stock Member
Beginning Balance at Dec. 31, 2020			$ 49,187	$ 122,535	$ 2,670,328	$ (310,856)	$ (743,620)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		$ 190,580			190,580
Other Comprehensive Income (Loss), Net of Tax		2,046				2,046
Dividends paid					(21,614)
Restricted stock				(9,007)			9,007
Employee stock purchase plan				877			8,828
Share-based compensation				10,724			137
Repurchases of common stock	[1]						(79,092)
Other				(597)			597
Ending Balance at Sep. 30, 2021			49,187	124,532	2,839,294	(308,810)	(804,143)
Beginning Balance at Jun. 30, 2021			49,187	119,946	2,776,884	(297,531)	(753,782)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		69,703			69,703
Other Comprehensive Income (Loss), Net of Tax		(11,279)				(11,279)
Dividends paid					(7,293)
Employee stock purchase plan				466			4,320
Share-based compensation				4,120			16
Repurchases of common stock	[1]						(54,697)
Ending Balance at Sep. 30, 2021			49,187	124,532	2,839,294	(308,810)	(804,143)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax		120,391
Ending Balance at Dec. 31, 2021		1,826,490	49,187	127,104	2,908,827	(190,465)	(1,068,163)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		185,325			185,325
Other Comprehensive Income (Loss), Net of Tax		(83,649)				(83,649)
Dividends paid					(21,513)
Restricted stock				(8,523)			8,523
Employee stock purchase plan				1,273			8,724
Share-based compensation				11,882			145
Repurchases of common stock	[1]						(44,434)
Other				(506)			506
Ending Balance at Sep. 30, 2022		1,884,243	49,187	131,230	3,072,639	(274,114)	(1,094,699)
Beginning Balance at Jun. 30, 2022			49,187	126,316	3,006,164	(227,872)	(1,086,156)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings		73,768			73,768
Other Comprehensive Income (Loss), Net of Tax		(46,242)				(46,242)
Dividends paid					(7,293)
Employee stock purchase plan				459			4,254
Share-based compensation				4,455			(8)
Repurchases of common stock	[1]						(12,789)
Ending Balance at Sep. 30, 2022		$ 1,884,243	$ 49,187	$ 131,230	$ 3,072,639	$ (274,114)	$ (1,094,699)

[1] For the three and nine months ended September 30, 2022, the Corporation repurchased approximately 0.1 million and 0.3 million shares of its common stock, respectively. For the three and nine months ended September 30, 2021, the Corporation repurchased approximately 0.4 million and 0.6 million shares of its common stock, respectively.