Equity-Based Compensation (Summary Of Stock Option Activity) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012
Equity-Based Compensation [Abstract]
Shares, Outstanding at beginning of year	1,702,650
Shares, Exercised	(48,561)
Shares, Granted	0
Shares, Forfeited	(1,663)
Shares, Expired	(12,150)
Shares, Outstanding at end of period	1,640,276
Shares, Exercisable at end of period	1,538,022
Weighted-Average Exercise Price, Granted	$ 0.00
Weighted-Average Exercise Price, Outstanding at beginning of year	$ 40.43
Weighted-Average Exercise Price, Exercised	$ 26.94
Weighted-Average Exercise Price, Forfeited	$ 36.36
Weighted-Average Exercise Price, Expired	$ 45.93
Weighted-Average Exercise Price, Outstanding at end of period	$ 40.79
Weighted-Average Exercise Price, Exercisable at end of period	$ 41.18
Intrinsic value of exercised options	$ 545,701