Incentive Plan (Summary Of Incentive Award Plan's Stock Option) (Details)	3 Months Ended
	Mar. 31, 2016 $ / shares shares
Shares
Options outstanding, end of period (shares) | shares	51,622
Exercised (shares) | shares	(28,345)
Options outstanding, end of period (shares) | shares	23,277
Exercisable, end of period (shares) | shares	23,277
Weighted average exercise price
Options outstanding, beginning of period ($ per share) | $ / shares	$ 41.04
Exercised ($ per share) | $ / shares	40.47
Options outstanding, end of period ($ per share) | $ / shares	41.73
Exercisable, end of period ($ per share) | $ / shares	$ 41.73