STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Retained Earnings Member Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income Member	Accumulated Other Comprehensive Income Member Cumulative Effect, Period of Adoption, Adjustment [Member]	Treasury Stock Member
Beginning Balance at Dec. 31, 2017		$ 49,187	$ 120,609	$ 1,944,324	$ (2,274)	$ (216,840)		$ (369,480)
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201802Member
Net earnings	$ 275,749			275,749
Other Comprehensive Income (Loss), Net of Tax	(71,607)					(71,607)
Dividends paid				(26,328)
Restricted Stock			(13,134)					13,134
Stock options exercised, net			(2,355)					14,294
Other			(752)	0				752
Share-based compensation			13,866					228
Repurchase of common stock								(198,592)
Ending Balance at Dec. 31, 2018		49,187	118,234	2,191,471	$ 26,257	(288,447)	$ (26,257)	(539,664)
Net earnings	307,583			307,583
Other Comprehensive Income (Loss), Net of Tax	(10,570)					(10,570)
Dividends paid				(28,200)
Restricted Stock			(10,483)					10,483
Stock options exercised, net			(4,226)					15,996
Other			(719)					719
Share-based compensation			13,264					405
Repurchase of common stock								(50,661)
Ending Balance at Dec. 31, 2019	1,774,372	49,187	116,070	2,497,111		(325,274)		(562,722)
Net earnings	201,392
Other Comprehensive Income (Loss), Net of Tax	14,418					14,418
Dividends paid				(28,175)
Restricted Stock			(4,115)					4,115
Stock options exercised, net			(3,286)					14,434
Other			(517)					517
Share-based compensation			14,383					54
Repurchase of common stock								(200,018)
Ending Balance at Dec. 31, 2020	$ 1,787,574	$ 49,187	$ 122,535	$ 2,670,328		$ (310,856)		$ (743,620)