Summary of Information Regarding Stock Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
Sep. 29, 2012
Number of Options
Beginning Balance	2,326,776
Granted	329,500
Exercised	(838,795)
Forfeited	(20,800)
Ending Balance	1,796,681
Options exercisable at September 29, 2012	667,864
Weighted Average Exercise Price per Share
Beginning Balance	$ 40.11
Granted	$ 52.03
Exercised	$ 39.53
Forfeited	$ 43.56
Ending Balance	$ 42.52
Options exercisable at September 29, 2012	$ 40.55
Weighted Average Remaining Contractual Term (years)
Options outstanding at September 29, 2012	6 years 3 months 18 days
Options exercisable at September 29, 2012	4 years 4 months 24 days
Aggregate Intrinsic Value
Options outstanding at September 29, 2012	$ 8,545
Options exercisable at September 29, 2012	$ 4,495

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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.

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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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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