Stock Based Compensation (Details) (USD $) In Millions, except Share data	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Share Based Compensation (Textuals) [Abstract]
Restricted stock awards granted, Shares			210,134
Restricted stock awards granted value			$ 15.8
Restricted stock awards expected to vest over vesting period.			193,550
Stock options			184,700
Stock options, Value	$ 75.37		$ 75.37
Stock based compensation pre-tax expense recognized	3.8	3.1	7.2	6.8
Stock based compensation expense recognized per diluted share after tax	$ 0.05	$ 0.04	$ 0.10	$ 0.10
Total fair value of restricted stock awards vested			12.2	7.4
Compensation cost related to unvested stock options	$ 31.1		$ 31.1

Allocated Share Based Compensation Net of Tax Per share.

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Restricted stock awards Expected to vest over vesting period.

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Share based compensation.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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The total fair value of equity-based awards for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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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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Total number of shares issued during the period, including shares forfeited, as a result of Restricted Stock Awards.

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Aggregate value of stock related to Restricted Stock Awards issued during the period.

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