Acquired Intangibles Assets and Liabilities - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquired Intangible Assets and Liabilities
Amortization of acquired above and below-market leases, net	$ 465	$ 865	$ 659
Amortization of all other identified intangible assets	15,000	18,200	$ 19,000
Estimated amortization of all other identified intangible assets
Net Carrying Value	95,451	$ 109,451
Acquired favorable and unfavorable leases
Estimated amortization of acquired favorable and unfavorable leases Rental Revenue
2019	479
2020	647
2021	46
2022	17
2023	17
Thereafter	(1,446)
Total	1,205
Estimated amortization of acquired favorable and unfavorable leases Rental Expense
2019	(166)
2020	(166)
2021	(166)
2022	(166)
2023	(166)
Total	615
All other identified intangible assets
Estimated amortization of all other identified intangible assets
2019	11,965
2020	11,379
2021	10,137
2022	9,910
2023	9,910
Thereafter	28,339
Net Carrying Value	$ 81,640