Income per Common Share of the Trust - Units and Distributions (Details) - Common shares [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Class of Stock [Line Items]
Increase in shares of the Trust/units of general partner from the conversion of limited partners' units	14,491	3,000	157,285
Distributions per common share	$ 1.90	$ 1.90	$ 1.90