Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013
Shares
Outstanding as of the beginning of the period	928	1,029
Exercised
Forfeited/expired/cancelled	(379)	(98)
Outstanding at the end of the period	549	931
Options exercisable at end of period	549	931
Aggregate intrinsic value of options exercised during the period
Weighted Average Exercise Price
Outstanding as of the beginning of the period	$ 29.68	$ 29.04
Exercised
Forfeited/expired/cancelled	$ 24.62	$ 23.17
Outstanding at the end of the period	$ 32.99	$ 29.66
Options exercisable at end of period	$ 32.99	$ 29.66

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

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

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

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Weighted average price of options that were either forfeited or expired.

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Number of options outstanding, including both vested and non-vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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

+ References

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