Summary of Nonvested Stock Option Transactions (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Nonvested at December 31, 2013	679
Number of options, Granted	0
Number of options, Cancelled	0
Number of options, Vested	(397)
Number of options, Nonvested at December 31, 2014	282
Weighted average grant date fair value, Nonvested at December 31, 2013	$ 6.88
Weighted average grant date fair value, Granted	$ 0	$ 7.50
Weighted average grant date fair value, Cancelled	$ 0
Weighted average grant date fair value, Vested	$ 7.04
Weighted average grant date fair value, Nonvested at December 31, 2014	$ 6.66

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Gross number of share options (or share units) granted during the period.

+ References

No definition available.

+ Details

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(1)

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

+ Details

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- Definition

Number of non-vested options outstanding.

+ References

No definition available.

+ Details

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- Definition

Number of non-vested options forfeited.

+ References

No definition available.

+ Details

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- Definition

Weighted average grant-date fair value of non-vested options forfeited.

+ References

No definition available.

+ Details

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- Definition

Weighted average grant-date fair value of non-vested options outstanding.

+ References

No definition available.

+ Details

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- Definition

Number of options vested.

+ References

No definition available.

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- Definition

Weighted average grant-date fair value of options vested.

+ References

No definition available.

+ Details

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