v2.4.0.8

Share-Based Compensation - Market Stock Units - Additional Information (Detail) (Market Stock Units [Member], USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended
	Nov. 30, 2012	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period, tranche one	1 year
Vesting period, tranche two	2 years
Vesting period, tranche three	3 years
Potential payout range		100.00%
Potential payout adjustment ratio	2
Number of MSUs granted		0
Shares under our MSU awards delivered		0
Shares under our MSU awards forfeited		0
Weighted average grant date fair value for the MSUs granted		$ 25.82
Unrecognized share-based compensation cost		$ 1.3
Unrecognized share-based compensation, period for recognition		1 year
Aggregate intrinsic value of MSUs		$ 2.9
Aggregate intrinsic value of stock option outstanding calculated using the closing price of common stock		$ 43.52
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential payout range	0.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential payout range	200.00%

X

- Definition

Percentage of potential payout.

+ References

No definition available.

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- Definition

Potential payout adjustment ratio.

+ References

No definition available.

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X

- Definition

Share based compensation arrangement by share based payment award, award vesting period tranche one.

+ References

No definition available.

+ Details

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X

- Definition

Share based compensation arrangement share based payment award, award vesting period tranche three.

+ References

No definition available.

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- Definition

Share based compensation arrangement by share based payment award award vesting period tranche two.

+ References

No definition available.

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X

- Definition

Share based compensation arrangement by share based payment award intrinsic value closing price.

+ References

No definition available.

+ Details

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X

- 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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

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

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X

- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

No definition available.

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X

- Definition

Intrinsic value of equity-based compensation awards outstanding. Excludes stock and unit options.

+ References

No definition available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ 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)(1)(iv)(3)

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

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X

- Definition

The number of grants made 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)

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

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X

- 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)

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

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X

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ 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)(2)

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

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