Equity-Based Compensation (Summary Of Outstanding And Exercisable SARs Options) (Detail) (USD $)	6 Months Ended
Jun. 30, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	1,639,718
Number of Shares, Exercisable	1,634,032
Aggregate intrinsic value, Outstanding	$ 2,421,000
Aggregate intrinsic value, Exercisable	2,318,000
Weighted-average remaining contractual term, Outstanding	3 years 9 months 18 days
Weighted-average remaining contractual term, Exercisable	3 years 9 months 18 days
Stock Option And Stock Appreciation Rights (SARs) [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	1,661,167
Number of Shares, Exercisable	572,231
Aggregate intrinsic value, Outstanding	11,705,000
Aggregate intrinsic value, Exercisable	$ 6,670,000
Weighted-average remaining contractual term, Outstanding	8 years 3 months 18 days
Weighted-average remaining contractual term, Exercisable	7 years 6 months
$ 1.29-$36.49 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 1.29
Range of Exercise Prices, Maximum	$ 36.49
Number of Shares, Outstanding	477,100
Weighted-Average Remaining Contractual Life, Outstanding (years)	4 years 7 months 2 days
Weighted-Average Exercise Price, Outstanding	$ 32.25
Number of Shares, Exercisable	471,414
Weighted-Average Exercise Price, Exercisable	$ 32.41
$ 36.80-$41.25 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 36.80
Range of Exercise Prices, Maximum	$ 41.25
Number of Shares, Outstanding	384,646
Weighted-Average Remaining Contractual Life, Outstanding (years)	4 years 9 months 22 days
Weighted-Average Exercise Price, Outstanding	$ 39.80
Number of Shares, Exercisable	384,646
Weighted-Average Exercise Price, Exercisable	$ 39.80
$ 42.28-$45.62 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 42.28
Range of Exercise Prices, Maximum	$ 45.62
Number of Shares, Outstanding	401,316
Weighted-Average Remaining Contractual Life, Outstanding (years)	3 years 2 months 27 days
Weighted-Average Exercise Price, Outstanding	$ 44.51
Number of Shares, Exercisable	401,316
Weighted-Average Exercise Price, Exercisable	$ 44.51
$ 46.18-$51.62 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 46.18
Range of Exercise Prices, Maximum	$ 51.62
Number of Shares, Outstanding	374,856
Weighted-Average Remaining Contractual Life, Outstanding (years)	2 years 5 months 12 days
Weighted-Average Exercise Price, Outstanding	$ 48.63
Number of Shares, Exercisable	374,856
Weighted-Average Exercise Price, Exercisable	$ 48.63
$ 53.92-$53.92 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 53.92
Range of Exercise Prices, Maximum	$ 53.92
Number of Shares, Outstanding	1,800
Weighted-Average Remaining Contractual Life, Outstanding (years)	1 year 10 months 28 days
Weighted-Average Exercise Price, Outstanding	$ 53.92
Number of Shares, Exercisable	1,800
Weighted-Average Exercise Price, Exercisable	$ 53.92
$ 19.56-$19.56 [Member] \| Stock Option And Stock Appreciation Rights (SARs) [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 19.56
Range of Exercise Prices, Maximum	$ 19.56
Number of Shares, Outstanding	387,075
Weighted-Average Remaining Contractual Life, Outstanding (years)	6 years 9 months 7 days
Weighted-Average Exercise Price, Outstanding	$ 19.56
Number of Shares, Exercisable	272,497
Weighted-Average Exercise Price, Exercisable	$ 19.56
$ 21.83-$27.50 [Member] \| Stock Option And Stock Appreciation Rights (SARs) [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 21.83
Range of Exercise Prices, Maximum	$ 27.50
Number of Shares, Outstanding	57,014
Weighted-Average Remaining Contractual Life, Outstanding (years)	7 years 4 months 6 days
Weighted-Average Exercise Price, Outstanding	$ 24.83
Number of Shares, Exercisable	39,708
Weighted-Average Exercise Price, Exercisable	$ 24.55
$ 27.82-$27.82 [Member] \| Stock Option And Stock Appreciation Rights (SARs) [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 27.82
Range of Exercise Prices, Maximum	$ 27.82
Number of Shares, Outstanding	413,710
Weighted-Average Remaining Contractual Life, Outstanding (years)	7 years 9 months 18 days
Weighted-Average Exercise Price, Outstanding	$ 27.82
Number of Shares, Exercisable	137,065
Weighted-Average Exercise Price, Exercisable	$ 27.82
$ 28.33-$40.10 [Member] \| Stock Option And Stock Appreciation Rights (SARs) [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 28.33
Range of Exercise Prices, Maximum	$ 40.10
Number of Shares, Outstanding	461,104
Weighted-Average Remaining Contractual Life, Outstanding (years)	9 years 8 months 1 day
Weighted-Average Exercise Price, Outstanding	$ 38.05
Number of Shares, Exercisable	24,755
Weighted-Average Exercise Price, Exercisable	$ 35.17
$ 40.10-$42.36 [Member] \| Stock Option And Stock Appreciation Rights (SARs) [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum	$ 40.10
Range of Exercise Prices, Maximum	$ 42.36
Number of Shares, Outstanding	342,264
Weighted-Average Remaining Contractual Life, Outstanding (years)	8 years 9 months 22 days
Weighted-Average Exercise Price, Outstanding	$ 41.61
Number of Shares, Exercisable	98,206
Weighted-Average Exercise Price, Exercisable	$ 41.70

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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- Definition

Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

+ 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

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-Publisher FASB

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-Paragraph A240

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-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

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

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

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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

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

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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

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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)

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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.

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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.

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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.

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