Summary of Significant Accounting Policies - Future Amortization of Deferred Expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Year Ending December 31,
2020 (Remaining)	$ 31,280
2021	29,979
2022	29,319
2023	28,037
2024	25,936
Thereafter	191,242
Total	335,793
Total	(33,019)	$ (26,668)
Lease Intangibles (In-place)
Year Ending December 31,
2020 (Remaining)	16,380
2021	14,426
2022	14,138
2023	13,098
2024	11,925
Thereafter	61,972
Total	131,939
Lease Intangibles (Above-Market)
Year Ending December 31,
2020 (Remaining)	20,828
2021	20,585
2022	19,609
2023	18,442
2024	16,916
Thereafter	140,493
Total	236,873
Lease Intangibles (Below-Market)
Year Ending December 31,
2020 (Remaining)	(5,928)
2021	(5,032)
2022	(4,428)
2023	(3,503)
2024	(2,905)
Thereafter	(11,223)
Total	$ (33,019)