Employee service share based compensation recognized period costs capitalized amount.

No definition available.

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- Definition

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

+ References

No definition available.

+ Details

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- Definition

Estimated forfeiture rate for unvested options for senior management.

+ References

No definition available.

+ Details

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- Definition

Expiration period of stock option plan.

+ References

No definition available.

+ Details

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- Definition

Number of groups within employee population.

+ References

No definition available.

+ Details

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- Definition

Number of stock option plans.

+ References

No definition available.

+ Details

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Data Type:	xbrli:positiveIntegerItemType
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- Definition

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

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (h)(1)(i)

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph g(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 14

-Section F

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 14.F)

-URI http://asc.fasb.org/extlink&oid=6793087&loc=d3e301413-122809

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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.

+ References

+ Details

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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.

+ References

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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.

+ References

+ Details

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Balance Type:	credit
Period Type:	duration

- 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.

+ References

+ Details

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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

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- 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 Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: 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

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Stock-Based Compensation Expense - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012 Employees OptionPlan	Oct. 02, 2011	Sep. 30, 2012 Employees OptionPlan	Oct. 02, 2011	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans	6,306,506		6,306,506
Number of stock option plans	2		2
Weighted-average grant-date fair values of stock options granted	$ 12.96	$ 11.89	$ 13.16	$ 11.78
Number of groups within the employee population	2		2
Percentage of stock options granted to senior management expected to vest	67.00%		67.00%
Percentage of stock options granted to all other employees expected to vest	66.00%		66.00%
Estimated forfeiture rate for unvested options for senior management	12.00%		12.00%
Estimated forfeiture rate for unvested options for all non-senior management	14.00%		14.00%
Stock-based compensation expense	$ 1,492,000	$ 1,520,000	$ 6,795,000	$ 5,829,000
Income tax benefit recognized related to stock-based compensation expense	478,000	502,000	2,212,000	1,947,000
Compensation expense was capitalized	0		0		0
Total intrinsic values of stock options exercised	1,436,000	5,254,000	14,744,000	17,808,000
Total unrecognized compensation expense related to non-vested stock options	$ 8,273,000		$ 8,273,000
Weighted-average period for unrecognized compensation expense related to non-vested stock options (years)			1 year 6 months
General Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under stock option plans	4,940,521		4,940,521
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	1,365,985		1,365,985
Expiration period of stock option plan			10 years
Vesting period for stock option plans			4 years