Intangibles - Amortization of Acquired Lease Intangibles (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Future aggregate net amortization of acquired lease intangibles (Net decrease in Revenue)
2018	$ (3,355)
2019	(3,376)
2020	(3,392)
2021	(3,333)
2022	(2,872)
Thereafter	(16,516)
Total	(32,844)
Future aggregate net amortization of acquired lease intangibles (Net Increase in Expenses)
2018	41,455
2019	36,429
2020	33,009
2021	30,582
2022	26,225
Thereafter	143,548
Total	$ 311,248