Summary of Significant Accounting Policies (Foreign Currency Translation) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016 USD ($) property	Dec. 31, 2015 USD ($) property	Dec. 31, 2014 USD ($) property	Jul. 28, 2008 property
Finite-Lived Intangible Assets [Line Items]
Foreign currency translation loss | $	$ 0.6	$ 2.5	$ 2.3
Unconsolidated properties
Finite-Lived Intangible Assets [Line Items]
Number of properties	17			22
Number of properties sold	1	3	1