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 $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net Earnings Attributable to Shareholders
Basic earnings attributable to shareholders	$ 91,302	$ 92,315	$ 175,126	$ 172,630
Diluted earnings attributable to shareholders	$ 91,302	$ 92,315	$ 175,126	$ 172,630
Weighted Average Shares
Weighted average basic shares outstanding	196,451,912	206,444,464	198,772,260	206,459,701
Effect of dilutive potential common shares	674,331	748,070	710,672	962,104
Weighted average diluted shares outstanding	197,126,243	207,192,534	199,482,932	207,421,805
Earnings Per Share
Basic earnings attributable to shareholders per share	$ 0.46	$ 0.45	$ 0.88	$ 0.84
Diluted earnings attributable to shareholders per share	$ 0.46	$ 0.45	$ 0.88	$ 0.83

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 $)
In Thousands, except Share data, unless otherwise specified

3 Months Ended

6 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Net Earnings Attributable to Shareholders

Basic earnings attributable to shareholders

$ 91,302

$ 92,315

$ 175,126

$ 172,630

Diluted earnings attributable to shareholders

$ 91,302

$ 92,315

$ 175,126

$ 172,630

Weighted Average Shares

Weighted average basic shares outstanding

196,451,912

206,444,464

198,772,260

206,459,701

Effect of dilutive potential common shares

674,331

748,070

710,672

962,104

Weighted average diluted shares outstanding

197,126,243

207,192,534

199,482,932

207,421,805

Earnings Per Share

Basic earnings attributable to shareholders per share

$ 0.46

$ 0.45

$ 0.88

$ 0.84

Diluted earnings attributable to shareholders per share

$ 0.46

$ 0.45

$ 0.88

$ 0.83

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