Share Capital - Estimated Compensation Cost Related to Unvested Stock Options (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2014
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract]
Unrecognized estimated compensation costs (in thousands of U.S. dollars)	$ 1,256
Expected weighted average period of recognition of compensation cost (in months)	36 months
Expected remaining weighted average period of compensation cost to be recognized (in years)	1 year 9 months

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration