CONSOLIDATED STATEMENTS OF STOCKHOLDERS' INVESTMENT - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	$ 1,670,730	$ 1,595,087	$ 1,425,745
Net income	506,421	576,968	664,505
Foreign currency translation	30,151	(4,214)	(53,475)
Dividends declared	(278,422)	(277,727)	(265,244)
Stock issued for employee benefit plans	89,803	47,977	30,018
Issuance of restricted stock	0	0	0
Stock-based compensation expense	43,995	39,083	87,791
Repurchase of common stock	(182,745)	(306,444)	(303,492)
Ending Balance	$ 1,879,933	$ 1,670,730	1,595,087	$ 1,425,745
Cumulative Effect Change - ASU 2014-09				us-gaap:AccountingStandardsUpdate201409Member
Cumulative Effect Change
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 9,239
Ending Balance				$ 9,239
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance (in shares)	134,895	137,284	139,542
Beginning Balance	$ 13,490	$ 13,728	$ 13,954
Stock issued for employee benefit plans (in shares)	1,754	1,017	764
Stock issued for employee benefit plans	$ 175	$ 102	$ 76
Issuance of restricted stock (in shares)	192	28	297
Issuance of restricted stock	$ 19	$ 3	$ 30
Stock-based compensation expense (in shares)	0	0	0
Stock-based compensation expense	$ 0	$ 0	$ 0
Repurchase of common stock (in shares)	(2,543)	(3,434)	(3,319)
Repurchase of common stock	$ (254)	$ (343)	$ (332)
Ending Balance (in shares)	134,298	134,895	137,284	139,542
Ending Balance	$ 13,430	$ 13,490	$ 13,728	$ 13,954
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	546,646	521,486	444,280
Stock issued for employee benefit plans	(24,600)	(13,920)	(10,547)
Issuance of restricted stock	(19)	(3)	(30)
Stock-based compensation expense	43,995	39,083	87,783
Ending Balance	566,022	546,646	521,486	444,280
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	4,144,834	3,845,593	3,437,093
Net income	506,421	576,968	664,505
Dividends declared	(278,422)	(277,727)	(265,244)
Ending Balance	4,372,833	4,144,834	3,845,593	3,437,093
Retained Earnings | Cumulative Effect Change
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			9,239
Ending Balance				9,239
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(76,149)	(71,935)	(18,460)
Foreign currency translation	30,151	(4,214)	(53,475)
Ending Balance	(45,998)	(76,149)	(71,935)	(18,460)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance	(2,958,091)	(2,713,785)	(2,451,122)
Stock issued for employee benefit plans	114,228	61,795	40,489
Stock-based compensation expense	0	0	8
Repurchase of common stock	(182,491)	(306,101)	(303,160)
Ending Balance	$ (3,026,354)	$ (2,958,091)	$ (2,713,785)	$ (2,451,122)