Stock-Based Compensation (Summary Of The Status Of Nonvested Share Awards) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Nonvested Share Awards [Roll Forward]
Nonvested, Shares, Beginning Balance	882,803
Granted, Shares	70,003
Vested, Shares	(35,812)
Forfeited, Shares	(9,795)
Canceled, Shares	(25,827)
Nonvested, Shares, Ending Balance	881,372
Nonvested, Weighted Average Grant Date Fair Value, Beginning Balance	$ 34.62
Granted , Weighted Average Grant Date Fair Value	$ 35.46
Vested , Weighted Average Grant Date Fair Value	$ 34.65
Forfeited , Weighted Average Grant Date Fair Value	$ 24.35
Canceled, Weighted Average Grant Date	$ 30.59
Nonvested , Weighted Average Grant Date Fair Value, Ending Balance	$ 34.81