Consolidated Statements of Beneficiaries' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Distributions declared per Common Share	$ 0.18	$ 0.16
Cumulative Distributions [Member]
Distributions declared per Common Share	0.18	0.16
Noncontrolling Interest [Member]
Distributions declared per Common Share	$ 0.18	$ 0.16