Income Taxes (Narrative) (Details) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Abstract]
Unrecognized tax benefits accrued interest	$ 95,000	$ 171,000
Tax benefits associated with the exercise, vesting or disposition of stock under stock plans recognized as an adjustment of additional paid-in capital	7,879,000	7,832,000	68,000
Income taxes paid in cash	$ 63,483,000	$ 63,557,000	$ 27,518,000

Tax benefit associated with any equity-based compensation plan other than an employee stock ownership plan (ESOP). The tax benefit results from the deduction by the entity on its tax return for an award of stock that exceeds the cumulative compensation cost for common stock or preferred stock recognized for financial reporting. Includes any resulting tax benefit that exceeds the previously recognized deferred tax asset (excess tax benefits).

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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- Definition

This element represents the amount of interest expense accrued as of the date of the statement of financial position for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity.

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