Intangible Assets and Intangible Liabilities - Summary of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Intangible assets:
Gross amount	$ 536,610	$ 579,066
Accumulated amortization	(173,087)	(166,841)
Intangible assets, Net	363,523	412,225
Intangible liabilities:
Gross amount	197,593	208,367
Accumulated amortization	(63,845)	(55,349)
Intangible Liabilities, Net	$ 133,748	$ 153,018