Identified Intangible Assets and Liabilities - Schedule of Identified Intangible Assets and Intangible Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross amount	$ 130,665	$ 308,895
Accumulated amortization	(98,187)	(172,114)
Total, net	32,478	136,781
Gross amount	325,449	503,373
Accumulated amortization	(264,493)	(341,779)
Total, net	$ 60,956	$ 161,594