Equity Incentive Plans (Summary Of Nonvested Share Activity) (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Number of Shares, Outstanding at December 31, 2012	371,864
Number of Shares, Vested	(149,324)
Number of Shares, Outstanding at March 31, 2013	498,525
Number of Shares, Granted	280,193
Weighted Average Grant Date Fair Value, Outstanding at December 31, 2012	$ 46.00
Weighted Average Grant Date Fair Value, Granted	$ 51.64
Weighted Average Grant Date Fair Value, Vested	$ 45.26
Weighted Average Grant Date Fair Value, Outstanding at March 31, 2013	$ 49.35
Weighted Average Life Remaining, Outstanding at March 31, 2013 (in years)	1 year 3 months 5 days
Share based compensation, future vesting period minimum (in years)	4 years
Fair value of non-vested shares	$ 7.3	$ 6.7
Unamortized share-based compensation expense	$ 13.9
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	4,208
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 50.02