Acquired Intangibles Assets and Liabilities - Amortization (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired above and below-market leases, net	$ 100	$ 100	$ 121	$ 270
Amortization of all other identified intangible assets	3,300	$ 4,300	6,400	$ 8,300
Estimated amortization of all other identified intangible assets
Net Carrying Value	89,226		89,226		$ 95,451
Acquired favorable and unfavorable leases
Estimated amortization of acquired favorable and unfavorable leases Rental Revenue
2019 (July - December)	183		183
2020	664		664
2021	152		152
2022	51		51
2023	24		24
Thereafter	6		6
Total	1,080		1,080
Estimated amortization of acquired favorable and unfavorable leases Rental Expense
2019 (July - December)	(110)		(110)
2020	(216)		(216)
2021	(216)		(216)
2022	(216)		(216)
2023	(216)		(216)
Thereafter	(604)		(604)
Total	(1,578)		(1,578)
All other identified intangible assets
Estimated amortization of all other identified intangible assets
2019 (July - December)	6,648		6,648
2020	12,091		12,091
2021	10,587		10,587
2022	10,074		10,074
2023	10,070		10,070
Thereafter	28,520		28,520
Net Carrying Value	$ 77,990		$ 77,990