Incentive Plans (Schedule Of Issuance Of RSUs And Charges To Retained Earnings) (Details) (USD $) In Thousands	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010
Incentive Plans
Issuance of RSUs	140,613	163,146
Charge to retained earnings, net of estimated forfeitures	$ 5,337	$ 4,732

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