Intangible Assets and Intangible Liabilities - Summary of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Intangible assets:
Gross amount	$ 562,262	$ 579,066
Accumulated amortization	(189,209)	(166,841)
Intangible assets, Net	373,053	412,225
Intangible liabilities:
Gross amount	210,016	208,367
Accumulated amortization	(71,453)	(55,349)
Intangible Liabilities, Net	$ 138,563	$ 153,018