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	(5,049)		(1,239)	(4,682)	(872)
Exercise of stock options and restricted stock units, shares		22,388
Treasury Stock, Value, Acquired, Cost Method	(262,500)			(262,500)
Repurchases of common stock, shares		(224,808)
Adjustment to Additional Paid in Capital, Share-Based Compensation	4,575		4,575
Net earnings	149,663				149,663
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	23,181					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	71,124
Treasury Stock, Value, Acquired, Cost Method	$ (727,500)
Repurchases of common stock, shares	(557,310)
Net earnings	$ 538,114
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	37,073
Ending balance at Sep. 30, 2021	159,171	$ 448	820,272	(5,995,662)	5,631,965	(297,852)
Ending balance, shares at Sep. 30, 2021		22,985,655
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
Stock Issued During Period, Value, Treasury Stock Reissued	(7,081)		0	(7,889)	(808)
Exercise of stock options and restricted stock units, shares		35,488
Treasury Stock, Value, Acquired, Cost Method	(252,499)			(252,499)
Repurchases of common stock, shares		(166,772)
Adjustment to Additional Paid in Capital, Share-Based Compensation	4,737		4,737
Net earnings	203,688				203,688
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	4,740					4,740
Ending balance at Sep. 30, 2021	159,171	$ 448	820,272	(5,995,662)	5,631,965	(297,852)
Ending balance, shares at Sep. 30, 2021		22,985,655
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	80,466
Treasury Stock, Value, Acquired, Cost Method	$ (825,000)
Repurchases of common stock, shares	(629,380)
Net earnings	$ 606,668
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(69,290)
Ending balance at Sep. 30, 2022	$ (82,809)	$ 448	842,421	(7,064,513)	6,463,349	(324,514)
Ending balance, shares at Sep. 30, 2022	22,294,189	22,294,189
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
Stock Issued During Period, Value, Treasury Stock Reissued	(1,750)		0	(1,941)	(191)
Exercise of stock options and restricted stock units, shares		8,058
Treasury Stock, Value, Acquired, Cost Method	(275,000)			(275,000)
Repurchases of common stock, shares		(220,479)
Adjustment to Additional Paid in Capital, Share-Based Compensation	4,731		4,731
Net earnings	220,597				220,597
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(42,149)					(42,149)
Ending balance at Sep. 30, 2022	$ (82,809)	$ 448	$ 842,421	$ (7,064,513)	$ 6,463,349	$ (324,514)
Ending balance, shares at Sep. 30, 2022	22,294,189	22,294,189