CONSOLIDATED STATEMENTS OF STOCKHOLDERS' INVESTMENT - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance		$ 1,425,745		$ 1,257,847	$ 1,425,745	$ 1,257,847	$ 1,150,450
Net income	$ 187,150	$ 142,297	$ 152,556	$ 122,080	664,505	504,893	513,384
Cumulative Effect Change - ASU 2014-09								$ 9,239
Foreign currency translation					(53,475)	42,982	(23,496)
Dividends declared, $1.88 in 2018, $1.81 in 2017, and $1.74 in 2016 per share					(265,244)	(258,378)	(245,426)
Stock issued for employee benefit plans					$ 30,018	16,572	(17,405)
Issuance of restricted stock (in shares)					1,696,609
Issuance of restricted stock					$ 0	0	0
Stock-based compensation expense					87,791	41,814	38,554
Excess tax benefit on deferred compensation and employee stock plans							18,462
Repurchase of common stock					(303,492)	(179,985)	(176,676)
Ending Balance	$ 1,595,087		$ 1,425,745		$ 1,595,087	$ 1,425,745	$ 1,257,847
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance (in shares)		139,542,000		141,258,000	139,542,000	141,258,000	143,455,000
Beginning Balance		$ 13,954		$ 14,126	$ 13,954	$ 14,126	$ 14,345
Stock issued for employee benefit plans (in shares)					764,000	612,000	32,000
Stock issued for employee benefit plans					$ 76	$ 61	$ 3
Issuance of restricted stock (in shares)					297,000	97,000	221,000
Issuance of restricted stock					$ 30	$ 10	$ 22
Stock-based compensation expense (in shares)					0	1,000	17,000
Stock-based compensation expense					$ 0	$ 0	$ 3
Repurchase of common stock (in shares)					(3,319,000)	(2,426,000)	(2,467,000)
Repurchase of common stock					$ (332)	$ (243)	$ (247)
Ending Balance (in shares)	137,284,000		139,542,000		137,284,000	139,542,000	141,258,000
Ending Balance	$ 13,728		$ 13,954		$ 13,728	$ 13,954	$ 14,126
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance		444,280		419,280	444,280	419,280	379,444
Stock issued for employee benefit plans					(10,547)	(16,760)	(16,121)
Issuance of restricted stock					(30)	(10)	(22)
Stock-based compensation expense					87,783	41,770	37,517
Excess tax benefit on deferred compensation and employee stock plans							18,462
Ending Balance	521,486		444,280		521,486	444,280	419,280
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance		3,437,093		3,190,578	3,437,093	3,190,578	2,922,620
Net income					664,505	504,893	513,384
Dividends declared, $1.88 in 2018, $1.81 in 2017, and $1.74 in 2016 per share					(265,244)	(258,378)	(245,426)
Ending Balance	3,845,593		3,437,093		3,845,593	3,437,093	3,190,578
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance		(18,460)		(61,442)	(18,460)	(61,442)	(37,946)
Foreign currency translation					(53,475)	42,982	(23,496)
Ending Balance	(71,935)		(18,460)		(71,935)	(18,460)	(61,442)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance		(2,451,122)		$ (2,304,695)	(2,451,122)	(2,304,695)	(2,128,013)
Stock issued for employee benefit plans					40,489	33,271	(1,287)
Stock-based compensation expense					8	44	1,034
Repurchase of common stock					(303,160)	(179,742)	(176,429)
Ending Balance	(2,713,785)		$ (2,451,122)		$ (2,713,785)	$ (2,451,122)	$ (2,304,695)
ASU No. 2014-09
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ (4,200)	$ 2,100
ASU No. 2014-09 | Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative Effect Change - ASU 2014-09								$ 9,239