Deferred Costs, Acquired Lease Intangibles and Goodwill - Future Amortization Expense and Rental Revenue (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Future Rental Revenue [Abstract]
2018	$ 6,442
2019	6,689
2020	3,559
2021	2,857
2022	3,175
Thereafter	12,690
Future Rental Revenue	35,412
Ground lease [Member]
Future Amortization Expense [Abstract]
2018	7,831
2019	7,831
2020	7,831
2021	7,831
2022	7,831
Thereafter	329,074
Future Amortization Expense	368,229
Lease agreements [Member]
Future Amortization Expense [Abstract]
2018	18,650
2019	15,996
2020	13,046
2021	11,302
2022	10,485
Thereafter	41,549
Future Amortization Expense	$ 111,028