Stock Based Compensation - Outstanding and Exercisable Stock Options (Detail) (USD $)	12 Months Ended
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Outstanding	1,382,500
Weighted- Average Remaining Contractual Life (in years)	5 years 4 months 24 days
Weighted- Average Exercise Price	$ 41.29
Number Exercisable	3,834,573
Weighted- Average Remaining Contractual Life (in years)	3 years 9 months 4 days
Weighted- Average Exercise Price	$ 48.83
Exercise Price Range of $15.84 - $23.77 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Minimum	$ 15.84
Range of Exercise Price, Maximum	$ 23.77
Number Outstanding	180,000
Weighted- Average Remaining Contractual Life (in years)	8 years 11 months 27 days
Weighted- Average Exercise Price	$ 20.91
Number Exercisable	30,000
Weighted- Average Remaining Contractual Life (in years)	8 years 11 months 23 days
Weighted- Average Exercise Price	$ 22.12
Exercise Price Range of $23.78 - $39.61 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Minimum	$ 23.78
Range of Exercise Price, Maximum	$ 39.61
Number Outstanding	2,955,830
Weighted- Average Remaining Contractual Life (in years)	7 years 9 months
Weighted- Average Exercise Price	$ 29.79
Number Exercisable	1,060,830
Weighted- Average Remaining Contractual Life (in years)	6 years 10 months 10 days
Weighted- Average Exercise Price	$ 33.61
Exercise Price Range of $39.62 - $47.53 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Minimum	$ 39.62
Range of Exercise Price, Maximum	$ 47.53
Number Outstanding	1,234,243
Weighted- Average Remaining Contractual Life (in years)	2 years 5 months 16 days
Weighted- Average Exercise Price	$ 43.84
Number Exercisable	1,234,243
Weighted- Average Remaining Contractual Life (in years)	2 years 6 months 7 days
Weighted- Average Exercise Price	$ 43.84
Exercise Price Range of $47.54 - $63.38 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Minimum	$ 47.54
Range of Exercise Price, Maximum	$ 63.38
Number Outstanding	892,500
Weighted- Average Remaining Contractual Life (in years)	3 years 22 days
Weighted- Average Exercise Price	$ 60.41
Number Exercisable	892,500
Weighted- Average Remaining Contractual Life (in years)	2 years 10 months 6 days
Weighted- Average Exercise Price	$ 60.41
Exercise Price Range of $63.39 - $71.30 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Minimum	$ 63.39
Range of Exercise Price, Maximum	$ 71.30
Number Outstanding	492,000
Weighted- Average Remaining Contractual Life (in years)	2 years 3 months 18 days
Weighted- Average Exercise Price	$ 67.17
Number Exercisable	492,000
Weighted- Average Remaining Contractual Life (in years)	2 years 3 months 4 days
Weighted- Average Exercise Price	$ 67.17
Exercise Price Range of $71.31 - $78.89 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Price, Minimum	$ 71.31
Range of Exercise Price, Maximum	$ 78.89
Number Outstanding	125,000
Weighted- Average Remaining Contractual Life (in years)	2 years 9 months
Weighted- Average Exercise Price	$ 78.89
Number Exercisable	125,000
Weighted- Average Remaining Contractual Life (in years)	2 years 9 months
Weighted- Average Exercise Price	$ 78.89

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

+ Details

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- Definition

Weighted average remaining contractual term of exercisable stock options, 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 floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-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 (g)

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

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

-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 (c)(iii)

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

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ 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)(i)-(ii)

-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 b(1)(a, 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.

+ Details

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

+ Details

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- Definition

Weighted average remaining contractual term of outstanding stock options, 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 ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

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