Intangible Assets and Liabilities - Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Amortization of intangible assets	$ 71,713	$ 20,785	$ 25,112