Activity for Option Plans (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014
Shares Under Option
Shares Under Options outstanding, beginning balance	1,272
Shares Under Option, Granted	244
Shares Under Option, Exercised	(715)
Shares Under Option, Forfeited	(33)
Shares Under Options outstanding, ending balance	768
Shares Under Options, Options exercisable, ending balance	179
Weighted-Average Exercise Price
Weighted-Average Exercise Price of Options outstanding, beginning balance	$ 72.81
Weighted-Average Exercise Price, Granted	$ 102.91
Weighted-Average Exercise Price, Exercised	$ 72.27
Weighted-Average Exercise Price, Forfeited	$ 82.78
Weighted-Average Exercise Price of Options outstanding, ending balance	$ 82.45
Weighted-Average Exercise Price, Options exercisable, ending balance	$ 67.57

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)

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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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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.

+ References

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

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

+ References

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

+ References

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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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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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

+ References

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

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-Name Regulation S-X (SX)

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