Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2018	$ 590,063	$ 448	$ 764,717	$ (3,814,604)	$ 3,941,916	$ (302,414)
Beginning balance, shares at Dec. 31, 2018		24,921,963
Exercise of stock options and restricted stock units, shares	298,002	298,002
Exercise of stock options and restricted stock units, Value	$ (47,581)			(50,449)	(3,737)
Repurchases of Common Stock, Shares	(1,094,648)	(1,094,648)
Repurchases of Common Stock, Value	$ (774,999)			(774,999)
APIC, Share-based Payment Arrangement, Other, Increase for Cost Recognition	18,285		18,285
Net earnings	561,109				561,109
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(21,259)					(21,259)
Ending balance at Dec. 31, 2019	$ 420,780	$ 448	783,871	(4,539,154)	4,499,288	(323,673)
Ending balance, shares at Dec. 31, 2019		24,125,317
APIC, Share-based Payment Arrangement, Restricted Stock Unit, Increase for Cost Recognition			869
Exercise of stock options and restricted stock units, shares	162,176	162,176
Exercise of stock options and restricted stock units, Value	$ (26,719)			(30,568)	(6,431)
Repurchases of Common Stock, Shares	(815,652)	(815,652)
Repurchases of Common Stock, Value	$ (774,998)			(774,998)
APIC, Share-based Payment Arrangement, Other, Increase for Cost Recognition	18,687		18,687
Net earnings	602,739				602,739
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(11,252)					(11,252)
Ending balance at Dec. 31, 2020	$ 282,675	$ 448	805,140	(5,283,584)	5,095,596	(334,925)
Ending balance, shares at Dec. 31, 2020	23,471,841	23,471,841
APIC, Share-based Payment Arrangement, Restricted Stock Unit, Increase for Cost Recognition			2,582
Exercise of stock options and restricted stock units, shares	110,748	110,748
Exercise of stock options and restricted stock units, Value	$ (20,463)			(24,533)	(5,309)
Repurchases of Common Stock, Shares	(739,486)	(739,486)
Repurchases of Common Stock, Value	$ (999,998)			(999,998)
APIC, Share-based Payment Arrangement, Other, Increase for Cost Recognition	19,595		19,595
Net earnings	768,985				768,985
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	79,701					79,701
Ending balance at Dec. 31, 2021	$ 171,421	$ 448	825,974	$ (6,259,049)	$ 5,859,272	$ (255,224)
Ending balance, shares at Dec. 31, 2021	22,843,103	22,843,103
APIC, Share-based Payment Arrangement, Restricted Stock Unit, Increase for Cost Recognition			$ 1,239