Interim Consolidated Statements of Shareholders' Equity and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2020	$ 282,675	$ 448	$ 805,140	$ (5,283,584)	$ 5,095,596	$ (334,925)
Beginning balance, shares at Dec. 31, 2020		23,471,841
Stock Issued During Period, Value, Treasury Stock Reissued			(1,239)	(4,682)	(872)
Exercise of stock options and restricted stock units, shares		22,388
Treasury Stock, Value, Acquired, Cost Method				(262,500)
Repurchases of common stock, shares		(224,808)
Adjustment to Additional Paid in Capital, Share-Based Compensation			4,575
Net earnings					149,663
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent						23,181
Ending balance at Mar. 31, 2021	202,643	$ 448	810,954	(5,541,402)	5,244,387	(311,744)
Ending balance, shares at Mar. 31, 2021		23,269,421
Beginning balance at Dec. 31, 2020	$ 282,675	$ 448	805,140	(5,283,584)	5,095,596	(334,925)
Beginning balance, shares at Dec. 31, 2020		23,471,841
Exercise of stock options and restricted stock units, shares	35,636
Treasury Stock, Value, Acquired, Cost Method	$ (475,000)
Repurchases of common stock, shares	(390,538)
Net earnings	$ 334,426
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	32,333
Ending balance at Jun. 30, 2021	191,424	$ 448	815,535	(5,751,052)	5,429,085	(302,592)
Ending balance, shares at Jun. 30, 2021		23,116,939
Beginning balance at Mar. 31, 2021	202,643	$ 448	810,954	(5,541,402)	5,244,387	(311,744)
Beginning balance, shares at Mar. 31, 2021		23,269,421
Stock Issued During Period, Value, Treasury Stock Reissued	(2,784)		0	(2,849)	(65)
Exercise of stock options and restricted stock units, shares		13,248
Treasury Stock, Value, Acquired, Cost Method	(212,499)			(212,499)
Repurchases of common stock, shares		(165,730)
Adjustment to Additional Paid in Capital, Share-Based Compensation	4,581		4,581
Net earnings	184,763				184,763
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	9,152					9,152
Ending balance at Jun. 30, 2021	191,424	$ 448	815,535	(5,751,052)	5,429,085	(302,592)
Ending balance, shares at Jun. 30, 2021		23,116,939
Beginning balance at Dec. 31, 2021	$ 171,421	$ 448	825,974	(6,259,049)	5,859,272	(255,224)
Beginning balance, shares at Dec. 31, 2021	22,843,103	22,843,103
Stock Issued During Period, Value, Treasury Stock Reissued	$ (5,289)		(1,020)	(6,669)	(2,400)
Exercise of stock options and restricted stock units, shares		27,795
Treasury Stock, Value, Acquired, Cost Method	(275,000)			(275,000)
Repurchases of common stock, shares		(190,593)
Adjustment to Additional Paid in Capital, Share-Based Compensation	4,509		4,509
Net earnings	174,001				174,001
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	4,350					4,350
Ending balance at Mar. 31, 2022	84,570	$ 448	831,503	(6,527,380)	6,030,873	(250,874)
Ending balance, shares at Mar. 31, 2022		22,680,305
Beginning balance at Dec. 31, 2021	$ 171,421	$ 448	825,974	(6,259,049)	5,859,272	(255,224)
Beginning balance, shares at Dec. 31, 2021	22,843,103	22,843,103
Exercise of stock options and restricted stock units, shares	72,408
Treasury Stock, Value, Acquired, Cost Method	$ (550,000)
Repurchases of common stock, shares	(408,901)
Net earnings	$ 386,071
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(27,141)
Ending balance at Jun. 30, 2022	$ 7,262	$ 448	837,690	(6,791,454)	6,242,943	(282,365)
Ending balance, shares at Jun. 30, 2022	22,506,610	22,506,610
Beginning balance at Mar. 31, 2022	$ 84,570	$ 448	831,503	(6,527,380)	6,030,873	(250,874)
Beginning balance, shares at Mar. 31, 2022		22,680,305
Stock Issued During Period, Value, Treasury Stock Reissued	(12,421)		(1,496)	(10,925)	0
Exercise of stock options and restricted stock units, shares		44,613
Treasury Stock, Value, Acquired, Cost Method	(274,999)			(274,999)
Repurchases of common stock, shares		(218,308)
Adjustment to Additional Paid in Capital, Share-Based Compensation	4,691		4,691
Net earnings	212,070				212,070
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(31,491)					(31,491)
Ending balance at Jun. 30, 2022	$ 7,262	$ 448	$ 837,690	$ (6,791,454)	$ 6,242,943	$ (282,365)
Ending balance, shares at Jun. 30, 2022	22,506,610	22,506,610