Stock-Based Compensation (Schedule Of Fair Value Of The Restricted Stock Awards Granted During The Periods) (Details) - Restricted Stock [Member] - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Time Vested [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		461,799	486,578
Estimated fair value (in millions)	[1]	$ 11.4	$ 2.6
Time Vested [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		461,799	486,578
Estimated fair value (in millions)	[1]	$ 11.4	$ 2.6
Percentage of shares granted expected to be distributed		94.00%	94.00%
Time Vested [Member] | Non-employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		0	0
Estimated fair value (in millions)	[1]	$ 0.0	$ 0.0
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		152,373	152,373
Estimated fair value (in millions)	[1]	$ 4.0	$ 0.8
Performance Shares [Member] | Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		152,373	152,373
Estimated fair value (in millions)	[1]	$ 4.0	$ 0.8
Percentage of shares granted expected to be distributed		105.00%	52.00%
Performance Shares [Member] | Non-employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		0	0
Estimated fair value (in millions)	[1]	$ 0.0	$ 0.0

[1] Represents 100% of the grant date fair value. (We recognize the grant date fair value minus estimated forfeitures.)