Consolidated Statements of Beneficiaries' Equity (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Distributions declared per Common Share	$ 0.36	$ 0.32
Cumulative Distributions [Member]
Distributions declared per Common Share	0.36	0.32
Noncontrolling Interest [Member]
Distributions declared per Common Share	$ 0.36	$ 0.32