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	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net Earnings Attributable to Shareholders
Basic earnings attributable to shareholders	$ 102,381	$ 92,400	$ 277,507	$ 265,030
Diluted earnings attributable to shareholders	$ 102,381	$ 92,400	$ 277,507	$ 265,030
Weighted Average Shares
Weighted average basic shares outstanding	194,419,071	206,516,194	197,305,251	206,478,746
Effect of dilutive potential common shares	582,196	852,598	648,559	872,823
Weighted average diluted shares outstanding	195,001,267	207,368,792	197,953,810	207,351,569
Earnings Per Share
Basic earnings attributable to shareholders per share	$ 0.53	$ 0.45	$ 1.41	$ 1.28
Diluted earnings attributable to shareholders per share	$ 0.53	$ 0.45	$ 1.40	$ 1.28

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

9 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Net Earnings Attributable to Shareholders

Basic earnings attributable to shareholders

$ 102,381

$ 92,400

$ 277,507

$ 265,030

Diluted earnings attributable to shareholders

$ 102,381

$ 92,400

$ 277,507

$ 265,030

Weighted Average Shares

Weighted average basic shares outstanding

194,419,071

206,516,194

197,305,251

206,478,746

Effect of dilutive potential common shares

582,196

852,598

648,559

872,823

Weighted average diluted shares outstanding

195,001,267

207,368,792

197,953,810

207,351,569

Earnings Per Share

Basic earnings attributable to shareholders per share

$ 0.53

$ 0.45

$ 1.41

$ 1.28

Diluted earnings attributable to shareholders per share

$ 0.53

$ 0.45

$ 1.40

$ 1.28

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