Summary of Significant Accounting Policies - Construction in Progress (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Construction in progress	$ 21,305	$ 9,867
Park Van Ness
Property, Plant and Equipment [Line Items]
Construction in progress	18,690	7,901
Other
Property, Plant and Equipment [Line Items]
Construction in progress	$ 2,615	$ 1,966