Noncontrolling Interest of Unitholders in Operating Partnership - Additional Information (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) item $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) shares
Maximum
Noncontrolling Interest
Number of permitted exchange requests in a calendar year | item	2
Limited Partnership
Noncontrolling Interest
Total units	16,688,000	15,300,000
Units converted by limited partners into common shares	47,000	6,000	47,000
Common shares value | $	$ 754	$ 87	$ 700
Total units	47,000	6,000	47,000
Limited Partnership | Minimum
Noncontrolling Interest
Number of units which can be redeemed in single redemption	1,000
Operating Partnership
Noncontrolling Interest
Distributions per unit | $ / shares	$ 0.9600	$ 0.9300
Declared distributions | $	$ 4,005	$ 3,557