Intangibles - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Intangibles
Net recognition of loss in rental income from intangible amortization write offs	$ (0.2)	$ (0.9)
Weighted average amortization period for lease intangibles		17 years
Weighted average amortization period for lease intangible liability		20 years
In-place lease intangible
Intangibles
Finite-lived intangible assets, disposals	2.0	$ 2.6
Above market lease intangible accumulated amortization written off	$ 1.8	$ 1.9