Acquired Intangibles Assets and Liabilities - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Acquired Intangible Assets and Liabilities
Amortization of acquired above and below-market leases, net	$ 865	$ 659	$ (117)
Total	1,903	2,119
Amortization of all other identified intangible assets	18,200	19,000	$ 9,000
Estimated amortization of all other identified intangible assets
Net Carrying Value	109,451	$ 129,754
Acquired favorable and unfavorable leases
Acquired Intangible Assets and Liabilities
Total	1,903
Estimated amortization of acquired favorable and unfavorable leases Rental Revenue
2018	681
2019	479
2020	647
2021	46
2022	17
Thereafter	17
Total	1,887
Estimated amortization of acquired favorable and unfavorable leases Rental Expense
2018	216
2019	216
2020	216
2021	216
2022	216
Thereafter	823
All other identified intangible assets
Estimated amortization of all other identified intangible assets
2018	14,574
2019	11,965
2020	11,379
2021	10,137
2022	9,910
Thereafter	38,248
Net Carrying Value	$ 96,213