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Commitments and Contingencies - Narrative (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]      
Ground rent expenses $ 9,894 $ 11,870 $ 10,968
Contingent liability under letters of credit 61,002    
Outstanding obligations under construction agreements $ 41,906