Options Outstanding by Exercise Price Range (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012
6.08
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price upper range limit	$ 6.08
Number of options, outstanding	1
Weighted average remaining contractual life, Outstanding (in years)	1 year 1 month 17 days
Weighted average exercise price, Outstanding	$ 6.08
Number of options, Exercisable	1
Weighted average remaining contractual life, Exercisable (in years)	1 year 1 month 17 days
Weighted average exercise price, Exercisable	$ 6.08
16.80
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price upper range limit	$ 16.80
Number of options, outstanding	1,579
Weighted average remaining contractual life, Outstanding (in years)	6 months 29 days
Weighted average exercise price, Outstanding	$ 16.80
Number of options, Exercisable	1,579
Weighted average remaining contractual life, Exercisable (in years)	6 months 29 days
Weighted average exercise price, Exercisable	$ 16.80
18.56-21.95
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 18.56
Exercise price upper range limit	$ 21.95
Number of options, outstanding	290
Weighted average remaining contractual life, Outstanding (in years)	2 years 11 months 23 days
Weighted average exercise price, Outstanding	$ 21.80
Number of options, Exercisable	215
Weighted average remaining contractual life, Exercisable (in years)	2 years 10 months 6 days
Weighted average exercise price, Exercisable	$ 21.74
23.35-24.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 23.35
Exercise price upper range limit	$ 24.01
Number of options, outstanding	3,260
Weighted average remaining contractual life, Outstanding (in years)	2 years 7 days
Weighted average exercise price, Outstanding	$ 23.77
Number of options, Exercisable	3,260
Weighted average remaining contractual life, Exercisable (in years)	2 years 7 days
Weighted average exercise price, Exercisable	$ 23.77
26.47
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price upper range limit	$ 26.47
Number of options, outstanding	1,100
Weighted average remaining contractual life, Outstanding (in years)	3 years 6 months 26 days
Weighted average exercise price, Outstanding	$ 26.47
Number of options, Exercisable	900
Weighted average remaining contractual life, Exercisable (in years)	3 years 6 months 29 days
Weighted average exercise price, Exercisable	$ 26.47
26.77-29.49
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 26.77
Exercise price upper range limit	$ 29.49
Number of options, outstanding	1,903
Weighted average remaining contractual life, Outstanding (in years)	4 years 4 months 17 days
Weighted average exercise price, Outstanding	$ 29.15
Number of options, Exercisable	1,123
Weighted average remaining contractual life, Exercisable (in years)	4 years 5 months 9 days
Weighted average exercise price, Exercisable	$ 29.34
32.31-35.79
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 32.31
Exercise price upper range limit	$ 35.79
Number of options, outstanding	316
Weighted average remaining contractual life, Outstanding (in years)	4 years 2 months 12 days
Weighted average exercise price, Outstanding	$ 34.73
Number of options, Exercisable	110
Weighted average remaining contractual life, Exercisable (in years)	4 years 2 months 5 days
Weighted average exercise price, Exercisable	$ 34.52
42.85-47.27
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 42.85
Exercise price upper range limit	$ 47.27
Number of options, outstanding	114
Weighted average remaining contractual life, Outstanding (in years)	6 years 3 months 15 days
Weighted average exercise price, Outstanding	$ 45.02
Number of options, Exercisable	12
Weighted average remaining contractual life, Exercisable (in years)	4 years 10 months 10 days
Weighted average exercise price, Exercisable	$ 43.95
51.98-53.05
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 51.98
Exercise price upper range limit	$ 53.05
Number of options, outstanding	2,060
Weighted average remaining contractual life, Outstanding (in years)	5 years 4 months 17 days
Weighted average exercise price, Outstanding	$ 52.91
Number of options, Exercisable	905
Weighted average remaining contractual life, Exercisable (in years)	5 years 4 months 17 days
Weighted average exercise price, Exercisable	$ 52.97
53.67-55.95
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 53.67
Exercise price upper range limit	$ 55.95
Number of options, outstanding	2,825
Weighted average remaining contractual life, Outstanding (in years)	6 years 4 months 21 days
Weighted average exercise price, Outstanding	$ 54.49
Number of options, Exercisable	425
Weighted average remaining contractual life, Exercisable (in years)	6 years 5 months 1 day
Weighted average exercise price, Exercisable	$ 53.69
6.08-55.95
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 6.08
Exercise price upper range limit	$ 55.95
Number of options, outstanding	13,448
Weighted average remaining contractual life, Outstanding (in years)	3 years 10 months 6 days
Weighted average exercise price, Outstanding	$ 35.24
Number of options, Exercisable	8,530
Weighted average remaining contractual life, Exercisable (in years)	2 years 10 months 10 days
Weighted average exercise price, Exercisable	$ 28.20

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

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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

+ Details

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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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