Incentive Plan (Summary Of Incentive Award Plan's Stock Option) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013
Incentive Plan [Abstract]
Options outstanding, beginning of period, Shares	129,259
Exercised, Shares	(250)
Options outstanding, end of period, Shares	129,009
Exercisable, end of period, Shares	129,009
Options outstanding, beginning of period, Weighted average exercise price	$ 30.61
Exercised, Weighted average exercise price	$ 33.18
Options outstanding, end of period, Weighted average exercise price	$ 30.60
Exercisable, end of period, Weighted average exercise price	$ 30.60