Basic and Diluted Earnings per Share - Numerator and Denominator of the Basic and Diluted Per Share Computations for Earnings Attributable to Shareholders Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Earnings Attributable to Shareholders
Basic earnings attributable to shareholders	$ 191,307	$ 160,221	$ 497,520	$ 453,069
Diluted earnings attributable to shareholders	$ 191,307	$ 160,221	$ 497,520	$ 453,069
Weighted Average Shares
Weighted average basic shares outstanding	168,310	170,415	167,942	171,084
Effect of dilutive potential common shares	2,425	3,068	2,597	3,379
Weighted average diluted shares outstanding	170,735	173,483	170,539	174,463
Earnings Per Share
Basic earnings attributable to shareholders per share	$ 1.14	$ 0.94	$ 2.96	$ 2.65
Diluted earnings attributable to shareholders per share	$ 1.12	$ 0.92	$ 2.92	$ 2.60