Acquired Intangible Assets and Liabilities (Schedule of Future Amortization Finite Lived Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Acquired in-place lease value
Finite-Lived Intangible Assets [Line Items]
2018	$ 209,091
2019	147,137
2020	111,205
2021	86,583
2022	64,666
Thereafter	240,885
Net	859,567	$ 379,250
Tenant relationship value and trade names
Finite-Lived Intangible Assets [Line Items]
2018	123,786
2019	123,786
2020	123,786
2021	123,786
2022	123,792
Thereafter	1,189,422
Net	$ 1,808,358