Summary of Changes in Outstanding Options (Detail)	6 Months Ended
Jun. 30, 2014
Number of Options
Number of Options, Outstanding at December 31, 2013	444,420
Number of Options, Exercised	(147,308)
Number of Options, Forfeited and expired	(1,000)
Number of Options, Outstanding at June 30, 2014	296,112

Number of share options (or share units) exercised during the current period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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