CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock Member	Additional Paid In Capital Member	Retained Earnings Member	Retained Earnings Member Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss Member	Accumulated Other Comprehensive Loss Member Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock Member
Beginning Balance at Dec. 31, 2018		$ 49,187	$ 118,234	$ 2,191,471	$ 26,257	$ (288,447)	$ (26,257)	$ (539,664)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 218,175			218,175
Other Comprehensive Income (Loss), Net of Tax	(11,209)					(11,209)
Dividends paid/declared				(20,947)
Restricted stock			(5,491)					5,491
Stock options exercised			(2,720)					13,662
Other			(661)					661
Share-based compensation			10,857					405
Repurchases of common stock								(37,864)
Ending Balance at Sep. 30, 2019		49,187	120,219	2,414,956		(325,913)		(557,309)
Beginning Balance at Dec. 31, 2018		49,187	118,234	2,191,471	$ 26,257	(288,447)	$ (26,257)	(539,664)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other Comprehensive Income (Loss), Net of Tax	(10,570)
Ending Balance at Dec. 31, 2019	1,774,372	49,187	116,070	2,497,111		(325,274)		(562,722)
Beginning Balance at Jun. 30, 2019		49,187	116,835	2,339,703		(302,490)		(550,939)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	82,510			82,510
Other Comprehensive Income (Loss), Net of Tax	(23,423)					(23,423)
Dividends paid/declared				(7,257)
Stock options exercised			(898)					6,429
Share-based compensation			4,282					0
Repurchases of common stock								(12,799)
Ending Balance at Sep. 30, 2019		49,187	120,219	2,414,956		(325,913)		(557,309)
Beginning Balance at Dec. 31, 2019	1,774,372	49,187	116,070	2,497,111		(325,274)		(562,722)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	147,399			147,399
Other Comprehensive Income (Loss), Net of Tax	14,383					14,383
Dividends paid/declared				(21,221)
Restricted stock			(4,115)					4,115
Stock options exercised			(1,364)					11,272
Other			(517)					517
Share-based compensation			11,723					54
Repurchases of common stock								(137,155)
Ending Balance at Sep. 30, 2020	1,799,463	49,187	121,797	2,623,289		(310,891)		(683,919)
Beginning Balance at Jun. 30, 2020		49,187	118,467	2,565,727		(342,681)		(677,405)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	64,620			64,620
Other Comprehensive Income (Loss), Net of Tax	31,790					31,790
Dividends paid/declared				(7,058)
Stock options exercised			(1,470)					6,191
Share-based compensation			4,800					(163)
Repurchases of common stock								(12,542)
Ending Balance at Sep. 30, 2020	$ 1,799,463	$ 49,187	$ 121,797	$ 2,623,289		$ (310,891)		$ (683,919)