Incentive Plan (Summary of Incentive Award Plan's Stock Option) (Details)	3 Months Ended
	Mar. 31, 2017 $ / shares shares
Shares
Options outstanding, end of period (shares) | shares	17,674
Exercised (shares) | shares	(17,668)
Options outstanding, end of period (shares) | shares	6
Exercisable, end of period (shares) | shares	6
Weighted average exercise price
Options outstanding, beginning of period ($ per share) | $ / shares	$ 41.73
Exercised ($ per share) | $ / shares	41.73
Options outstanding, end of period ($ per share) | $ / shares	41.73
Exercisable, end of period ($ per share) | $ / shares	$ 41.73