Share-Based Compensation (Stock Option Plan) (Details) (USD $)	3 Months Ended
Mar. 31, 2012
Share-Based Compensation [Abstract]
Outstanding, Weighted Average Price Per Share, Beginning Balance	$ 10.97
Outstanding, Number of Shares, Beginning Balance	2,912,000
Granted, Weighted Average Price	$ 17.50
Granted, Number of Shares	601,000
Cancelled, Weighted Average Price	$ 12.37
Cancelled, Number of Shares	(16,000)
Exercised, Weighted Average Price	$ 10.08
Exercised, Number of Shares	(181,000)
Outstanding, Weighted Average Price Per Share, Ending Balance	$ 12.20
Outstanding, Number of Shares, Ending Balance	3,316,000
Outstanding, Weighted Average Remaining Contractual Life (In Years)	6.50
Outstanding, Aggregate Intrinsic Value	$ 30,094,000
Options exercisable, Weighted Average Remaining Contractual Life (In Years)	4.47
Options exercisable, Number of Shares	1,630,000
Options exercisable, Aggregate Intrinsic Value	$ 20,099,000

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of vested portions of options outstanding and currently exercisable under the option plan as of the balance sheet date.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted average period between the balance sheet date and expiration for all vested portions of options outstanding and currently exercisable (or convertible) under the plan, which may be expressed in a decimal value for number of years.

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- Definition

The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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The combined weighted average exercise price associated with stock options during the period that have either lapsed or been forfeited.

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Net number of share options (or share units) granted during the period.

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The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting period.

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance sheet date.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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The weighted-average period remaining as of the balance sheet date until option expiration pertaining to the outstanding stock options for all option plans in the customized range of exercise prices, which may be expressed in a variety of ways (for example, years, months).

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Number of share options (or share units) exercised during the current period.

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