Summary of Significant Accounting Policies - Future Amortization of Deferred Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Year Ending December 31,
2019	$ 22,123
2020	21,746
2021	20,823
2022	20,608
2023	19,825
Thereafter	151,588
Total	256,713
Total	(27,218)	$ (30,350)
Credit Facility Financing Costs [Member]
Year Ending December 31,
2019	556
2020	542
2021	28
Total	1,126
Leasing Costs [Member]
Year Ending December 31,
2019	290
2020	315
2021	306
2022	298
2023	312
Thereafter	1,131
Total	2,652
Lease Intangibles (Assets) [Member]
Year Ending December 31,
2019	25,690
2020	25,202
2021	24,517
2022	23,439
2023	22,080
Thereafter	159,225
Total	280,153
Lease Intangibles (Liability) [Member]
Year Ending December 31,
2019	(4,413)
2020	(4,313)
2021	(4,028)
2022	(3,129)
2023	(2,567)
Thereafter	(8,768)
Total	$ (27,218)