Incentive Plan (Summary Of Stock Options Outstanding And Exercisable) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number outstanding (shares)	72,932	80,933
Weighted-average remaining contractual life (years)	1 year 272 days
Weighted average exercise price, Outstanding ($ per share)	$ 36.76
Aggregate intrinsic value	$ 2,129,660
$20.37-20.37
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 20.37
Exercise price, upper limit	$ 20.37
Number outstanding (shares)	15,000
Weighted-average remaining contractual life (years)	0 years 221 days
Weighted average exercise price, Outstanding ($ per share)	$ 20.37
Aggregate intrinsic value	683,850
$33.18-41.73
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit	$ 33.18
Exercise price, upper limit	$ 41.73
Number outstanding (shares)	57,932
Weighted-average remaining contractual life (years)	2 years 18 days
Weighted average exercise price, Outstanding ($ per share)	$ 41.00
Aggregate intrinsic value	$ 1,445,810