Intangible Assets and Liabilities - Estimated Future Annual Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Intangible Assets, Net (Excluding Goodwill) [Abstract]
2019 Amortization	$ 72,512
2019 Accretion	(8,233)
2019 Amortization, net	64,279
2020 Amortization	52,591
2020 Accretion	(8,028)
2020 Amortization, net	44,563
2021 Amortization	37,124
2021 Accretion	(1,963)
2021 Amortization, net	35,161
2022 Amortization	26,950
2022 Accretion	(459)
2022 Amortization, net	26,491
2023 Amortization	19,363
2023 Accretion	0
2023 Amortization, net	19,363
Beyond 2023	45,943
Beyond 2023 Accretion	0
Beyond 2023 Amortization, net	45,943
Total intangible assets subject to amortization	254,483	$ 95,228
Finite-lived intangible liabilities, net	(18,683)	$ 0
Finite-lived intangible assets (liabilities), net	$ 235,800