Intangible Assets and Intangible Liabilities - Summary of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Intangible assets:
Gross amount	$ 621,466	$ 655,194
Accumulated amortization	(157,239)	(143,987)
Intangible assets, Net	464,227	511,207
Intangible liabilities:
Gross amount	221,052	221,672
Accumulated amortization	(53,983)	(41,931)
Intangible Liabilities, Net	$ 167,069	$ 179,741