Equity-Based Compensation (Summary Of Outstanding Stock Options By Exercise Price Range) (Details) (USD $)	9 Months Ended
	Sep. 30, 2011 Years
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding (in shares)	156,748
Weighted Avg. Remaining Contractual Life (in years)	2.21
Weighted Avg. Exercise Price (in dollars per share)	$ 22.82
$13.8594 to $16.6452 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit (in dollars per share)	$ 13.8594
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 16.6452
Options outstanding (in shares)	47,908
Weighted Avg. Remaining Contractual Life (in years)	0.93
Weighted Avg. Exercise Price (in dollars per share)	$ 14.89
$19.2569 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 19.2569
Options outstanding (in shares)	42,995
Weighted Avg. Remaining Contractual Life (in years)	2.17
Weighted Avg. Exercise Price (in dollars per share)	$ 19.26
$30.9204 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Upper Limit (in dollars per share)	$ 30.9204
Options outstanding (in shares)	65,845
Weighted Avg. Remaining Contractual Life (in years)	3.17
Weighted Avg. Exercise Price (in dollars per share)	$ 30.92