Numerator and Denominator of the Basic and Diluted Per Share Computations for Earnings Attributable to Shareholders Per Share (Detail) (USD $) In Thousands, except Share data	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Net Earnings Attributable to Shareholders
Basic earnings attributable to shareholders	$ 106,604	$ 96,105	$ 292,836	$ 247,670
Diluted earnings attributable to shareholders	$ 106,604	$ 96,105	$ 292,836	$ 247,670
Weighted Average Shares
Weighted average basic shares outstanding	212,256,119	212,392,286	212,160,994	212,306,521
Effect of dilutive potential common shares	2,461,332	3,950,094	3,215,681	4,191,317
Weighted average diluted shares outstanding	214,717,451	216,342,380	215,376,675	216,497,838
Earnings Per Share
Basic earnings attributable to shareholders per share	$ 0.50	$ 0.45	$ 1.38	$ 1.17
Diluted earnings attributable to shareholders per share	$ 0.50	$ 0.44	$ 1.36	$ 1.14

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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