Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Total shareholders' equity	Noncontrolling interest
Balance (in shares) at Dec. 31, 2014		191,656
Balance at Dec. 31, 2014	$ 1,871,608	$ 1,916	$ 1,113	$ 1,903,196	$ (37,817)	$ 1,868,408	$ 3,200
Increase (Decrease) in Equity [Roll Forward]
Exercise of stock options and release of restricted shares (in shares)		2,851
Exercise of stock options and release of restricted shares	105,114	$ 29	105,085			105,114
Issuance of shares under stock purchase plan (in shares)		699
Issuance of shares under stock purchase plan	25,850	$ 7	25,843			25,850
Shares repurchased under provisions of stock repurchase plans (in shares)		(13,139)
Shares repurchased under provisions of stock repurchase plans	(629,991)	$ (131)	(176,493)	(453,367)		(629,991)
Stock compensation expense	43,415		43,415			43,415
Tax benefits from stock plans, net	1,068		1,068			1,068
Net earnings	459,497			457,223		457,223	2,274
Other comprehensive income (loss)	(44,090)				(43,421)	(43,421)	(669)
Dividends paid	(135,673)			(135,673)		(135,673)
Distributions of dividends to noncontrolling interest	(2,122)						(2,122)
Balance (in shares) at Dec. 31, 2015		182,067
Balance at Dec. 31, 2015	1,694,676	$ 1,821	31	1,771,379	(81,238)	1,691,993	2,683
Increase (Decrease) in Equity [Roll Forward]
Exercise of stock options and release of restricted shares (in shares)		3,769
Exercise of stock options and release of restricted shares	157,177	$ 38	157,139			157,177
Issuance of shares under stock purchase plan (in shares)		703
Issuance of shares under stock purchase plan	28,136	$ 7	28,129			28,136
Shares repurchased under provisions of stock repurchase plans (in shares)		(6,682)
Shares repurchased under provisions of stock repurchase plans	(337,658)	$ (67)	(225,317)	(112,274)		(337,658)
Stock compensation expense	45,217		45,217			45,217
Tax benefits from stock plans, net	(2,664)		(2,664)			(2,664)
Net earnings	432,533			430,807		430,807	1,726
Other comprehensive income (loss)	(23,743)				(23,354)	(23,354)	(389)
Dividends paid	(145,123)			(145,123)		(145,123)
Purchase of noncontrolling interest	(3)		107			107	(110)
Distributions of dividends to noncontrolling interest	$ (1,335)						(1,335)
Balance (in shares) at Dec. 31, 2016	179,857	179,857
Balance at Dec. 31, 2016	$ 1,847,213	$ 1,799	2,642	1,944,789	(104,592)	1,844,638	2,575
Increase (Decrease) in Equity [Roll Forward]
Exercise of stock options and release of restricted shares (in shares)		4,058
Exercise of stock options and release of restricted shares	176,325	$ 40	176,285			176,325
Issuance of shares under stock purchase plan (in shares)		682
Issuance of shares under stock purchase plan	28,767	$ 7	28,760			28,767
Shares repurchased under provisions of stock repurchase plans (in shares)		(8,223)
Shares repurchased under provisions of stock repurchase plans	(478,258)	$ (82)	(258,049)	(220,127)		(478,258)
Stock compensation expense	50,908		50,908			50,908
Net earnings	490,383			489,345		489,345	1,038
Other comprehensive income (loss)	30,434				30,628	30,628	(194)
Dividends paid	(150,495)			(150,495)		(150,495)
Distributions of dividends to noncontrolling interest	$ (904)						(904)
Balance (in shares) at Dec. 31, 2017	176,374	176,374
Balance at Dec. 31, 2017	$ 1,994,373	$ 1,764	$ 546	$ 2,063,512	$ (73,964)	$ 1,991,858	$ 2,515