Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2013 Employees OptionPlan	Apr. 01, 2012	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans	5,620,604
Number of stock option plans	2
Expected dividend yield	0.00%	1.20%
Weighted-average grant-date fair values of stock options granted	$ 16.13	$ 12.98
Number of groups within the employee population	2
Percentage of stock options granted to senior management expected to vest	71.00%
Percentage of stock options granted to all other employees expected to vest	69.00%
Estimated forfeiture rate for unvested options for senior management	12.00%
Estimated forfeiture rate for unvested options for all non-senior management	13.00%
Stock-based compensation expense	$ 3,298,000	$ 3,314,000
Income tax benefit recognized related to stock-based compensation expense	1,094,000	1,087,000
Compensation expense was capitalized	0		0
Total intrinsic values of stock options exercised	7,193,000	12,636,000
Total fair values of stock options vested	6,932,000	6,399,000
Total unrecognized compensation expense related to non-vested stock options	$ 14,025,000
Weighted-average period for unrecognized compensation expense related to non-vested stock options (years)	1 year 8 months 12 days
2015 through expected life of option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	1.04%
General Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans	4,361,494
Expiration period of stock option plan	10 years
Vesting period for stock option plans	4 years
Stock Option and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans	1,259,110
Expiration period of stock option plan	10 years
Vesting period for stock option plans	4 years

Employee service share based compensation recognized period costs capitalized amount.

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- Definition

Estimated forfeiture rate for unvested options for all non-senior management.

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Estimated forfeiture rate for unvested options for senior management.

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- Definition

Expiration period of stock option plan.

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- Definition

Number of groups within employee population.

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- Definition

Number of stock option plans.

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- Definition

Percentage of stock options granted to all other employees expected to vest.

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- Definition

Percentage of stock options granted to senior management expected to vest.

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- Definition

Share based compensation arrangement by share based payment award options vested fair value.

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No definition available.

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- Definition

Shares based compensation arrangement by shares based payment award options exercisable intrinsic value.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-Paragraph A240

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

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- Definition

As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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- Definition

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.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

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

-Publisher FASB

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-Topic 718

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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

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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