Components of Equity (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares, outstanding	171,648		171,582
Beginning balance	$ 1,987,720	$ 1,994,373
Cumulative effect of accounting change		(22,462)
Exercise of stock options and release of restricted shares	27,190	26,397
Shares repurchased under provisions of stock repurchase plans	(44,334)	(172,360)
Stock compensation expense	13,382	11,267
Net earnings	140,111	136,200
Other comprehensive (loss) income	1,365	8,851
Ending balance	2,125,434	1,982,266
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(105,481)	(73,964)
Other comprehensive (loss) income	1,495	8,972
Ending balance	(103,986)	(64,992)
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	2,088,707	2,063,512
Cumulative effect of accounting change		(22,357)
Shares repurchased under provisions of stock repurchase plans	(5,844)	(135,327)
Net earnings	139,699	135,692
Ending balance	2,222,562	2,041,520
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,896	546
Exercise of stock options and release of restricted shares	27,184	26,391
Shares repurchased under provisions of stock repurchase plans	(38,484)	(37,006)
Stock compensation expense	13,382	11,267
Ending balance	$ 3,978	$ 1,198
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares, outstanding	171,648	174,308	171,582	176,374
Beginning balance	$ 1,716	$ 1,764
Exercise of stock options and release of restricted shares (In shares)	654	596
Exercise of stock options and release of restricted shares	$ 6	$ 6
Shares repurchased under provisions of stock repurchase plans, shares	(588)	(2,662)
Shares repurchased under provisions of stock repurchase plans	$ (6)	$ (27)
Ending balance	1,716	1,743
Shareholders' Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,986,838	1,991,858
Cumulative effect of accounting change		(22,357)
Exercise of stock options and release of restricted shares	27,190	26,397
Shares repurchased under provisions of stock repurchase plans	(44,334)	(172,360)
Stock compensation expense	13,382	11,267
Net earnings	139,699	135,692
Other comprehensive (loss) income	1,495	8,972
Ending balance	2,124,270	1,979,469
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	882	2,515
Cumulative effect of accounting change		(105)
Net earnings	412	508
Other comprehensive (loss) income	(130)	(121)
Ending balance	$ 1,164	$ 2,797