Incentive Plan (Summary of Stock Options Outstanding and Exercisable) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding (in shares)	17,674	51,622
$41.73
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 41.73
Exercise price, upper limit (in dollars per share)	$ 41.73
Number of options outstanding (in shares)	17,674
Weighted average remaining contractual life (years), Outstanding	4 months
Weighted average exercise price per option, Outstanding (in dollars per share)	$ 41.73
Aggregate intrinsic value, Outstanding	$ 999,111