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

Reference 1: 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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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 weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ 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 (c)(2)(iii)(1)

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-Publisher FASB

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-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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ 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 (c)(2)(i)-(ii)

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-Subparagraph b(2)(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.

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph a

-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.

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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

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-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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- Definition

The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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- Definition

Percentage of performance based award payouts.

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Additionally Authorized

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- Definition

Share based compensation by share based payment award, options term.

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Stock-Based Compensation Plans (Narrative) (Detail) (USD $)	3 Months Ended		9 Months Ended							9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Maximum [Member]	Sep. 30, 2012 2007 Plan [Member]	May 31, 2011 2007 Plan [Member]	May 31, 2009 2007 Plan [Member]	Sep. 30, 2012 2007 Plan [Member] Minimum [Member]	Sep. 30, 2012 2007 Plan [Member] Maximum [Member]	Sep. 30, 2012 1997 Plan [Member]	Sep. 30, 2012 Long-Term Incentive Program Awards [Member]	Sep. 30, 2012 Long-Term Incentive Program Awards [Member] Minimum [Member]	Sep. 30, 2012 Long-Term Incentive Program Awards [Member] Maximum [Member]	Sep. 30, 2012 Executive Officer [Member]	Sep. 30, 2012 Maximum Potential Issuances Based On Grants To Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares approved for issuance							500,000
Shares additionally approved for issuance								2,860,000	325,000
Shares available for future grants							1,304,844
Award vesting period, maximum, years					1 year	5 years				3 years	5 years		3 years
Share based payment award options term							7 years					10 years	7 years
Percentage of performance based award payouts														0.00%	200.00%
Compensation cost charged to income for stock options	$ 2,600,000	$ 1,400,000	$ 7,200,000	$ 3,400,000
Weighted average grant date fair value per share of options granted																$ 14.55
Aggregate intrinsic value of options exercised			$ 4,900,000	$ 823,000
Maximum number of performance-vested shares that could be issued																	430,440