Condensed Consolidated Statements of Stockholders' Investment - USD ($) shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 1,704,328	$ 1,587,118	$ 1,670,730	$ 1,659,311	$ 1,652,561	$ 1,595,087	$ 1,670,730	$ 1,595,087
Net income	136,529	143,939	78,146	146,894	169,180	161,788	358,614	477,862
Foreign currency adjustments, net of tax	13,236	24,253	(32,195)	(18,576)	(5,688)	5,297
Dividends declared	(70,188)	(69,791)	(69,871)	(68,855)	(69,268)	(69,683)
Stock issued for employee benefit plans	78,678	7,855	(2,526)	10,818	7,699	7,573
Issuance of restricted stock, net of forfeitures			0	0	0	0
Stock-based compensation expense	10,776	10,954	11,397	8,850	14,684	17,123
Repurchase of common stock			(68,563)	(65,346)	(109,857)	(64,624)
Ending balance	$ 1,873,359	$ 1,704,328	$ 1,587,118	$ 1,673,096	$ 1,659,311	$ 1,652,561	$ 1,873,359	$ 1,673,096
Dividends declared, per share (in dollars per share)	$ 0.51	$ 0.51	$ 0.51	$ 0.50	$ 0.50	$ 0.50
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	134,724	134,586	134,895	135,731	136,889	137,284	134,895	137,284
Beginning balance	$ 13,472	$ 13,459	$ 13,490	$ 13,573	$ 13,689	$ 13,728	$ 13,490	$ 13,728
Stock issued for employee benefit plans (in shares)	1,176	138	343	194	129	342
Stock issued for employee benefit plans	$ 118	$ 13	$ 34	$ 20	$ 13	$ 34
Issuance of restricted stock, net of forfeitures (in shares)			321	9	23
Issuance of restricted stock, net of forfeitures (in shares)						(3)
Issuance of restricted stock, net of forfeitures			$ 32	$ 1	$ 2	$ 0
Stock-based compensation expense (in shares)	0	0	0	0	0	0
Stock-based compensation expense	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Repurchase of common stock (in shares)			(973)	(782)	(1,310)	(734)
Repurchase of common stock			$ (97)	$ (79)	$ (131)	$ (73)
Ending balance (in shares)	135,900	134,724	134,586	135,152	135,731	136,889	135,900	135,152
Ending balance	$ 13,590	$ 13,472	$ 13,459	$ 13,515	$ 13,573	$ 13,689	$ 13,590	$ 13,515
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	543,608	533,819	546,646	541,090	527,089	521,486	546,646	521,486
Stock issued for employee benefit plans	1,032	(1,165)	(24,192)	(561)	(681)	(11,520)
Issuance of restricted stock, net of forfeitures			(32)	(1)	(2)	0
Stock-based compensation expense	10,776	10,954	11,397	8,850	14,684	17,123
Ending balance	555,416	543,608	533,819	549,378	541,090	527,089	555,416	549,378
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	4,227,257	4,153,109	4,144,834	4,037,610	3,937,698	3,845,593	4,144,834	3,845,593
Net income	136,529	143,939	78,146	146,894	169,180	161,788
Dividends declared	(70,188)	(69,791)	(69,871)	(68,855)	(69,268)	(69,683)
Ending balance	4,293,598	4,227,257	4,153,109	4,115,649	4,037,610	3,937,698	4,293,598	4,115,649
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(84,091)	(108,344)	(76,149)	(72,326)	(66,638)	(71,935)	(76,149)	(71,935)
Foreign currency adjustments, net of tax	13,236	24,253	(32,195)	(18,576)	(5,688)	5,297
Ending balance	(70,855)	(84,091)	(108,344)	(90,902)	(72,326)	(66,638)	(70,855)	(90,902)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(2,995,918)	(3,004,925)	(2,958,091)	(2,860,636)	(2,759,277)	(2,713,785)	(2,958,091)	(2,713,785)
Stock issued for employee benefit plans	77,528	9,007	21,632	11,359	8,367	19,059
Stock-based compensation expense	0	0	0	0	0	0
Repurchase of common stock			(68,466)	(65,267)	(109,726)	(64,551)
Ending balance	$ (2,918,390)	$ (2,995,918)	$ (3,004,925)	$ (2,914,544)	$ (2,860,636)	$ (2,759,277)	$ (2,918,390)	$ (2,914,544)