Components of Equity (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 1,847,213	$ 1,694,676
Exercise of stock options			134,014	119,509
Issuance of shares under stock purchase plan			28,767	28,136
Shares repurchased under provisions of stock repurchase plans			(340,736)	(268,097)
Stock compensation expense			39,036	34,264
Tax benefits from stock plans, net				(2,533)
Net earnings	$ 120,606	$ 107,949	322,928	321,435
Other comprehensive income (loss)	7,489	260	25,585	(457)
Dividends paid			75,726	73,000
Ending Balance	1,981,081	1,853,933	1,981,081	1,853,933
Shareholders' Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			1,844,638	1,691,993
Exercise of stock options			134,014	119,509
Issuance of shares under stock purchase plan			28,767	28,136
Shares repurchased under provisions of stock repurchase plans			(340,736)	(268,097)
Stock compensation expense			39,036	34,264
Tax benefits from stock plans, net				(2,533)
Net earnings			322,378	320,217
Other comprehensive income (loss)			25,632	(406)
Dividends paid			75,726	73,000
Ending Balance	1,978,003	1,850,083	1,978,003	1,850,083
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			2,575	2,683
Net earnings			550	1,218
Other comprehensive income (loss)			(47)	(51)
Ending Balance	$ 3,078	$ 3,850	$ 3,078	$ 3,850