Summary of Significant Accounting Policies - Deferred Costs and Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Deferred costs and intangible assets, net:
In-place lease value, net	$ 7,338	$ 14,559
Goodwill	21,387	21,387
Other intangible assets	380	380
Subtotal intangible assets	29,105	36,326
Deferred costs, net	185	670
Total	$ 29,290	$ 36,996