Identified Intangible Assets and Liabilities - Schedule of Identified Intangible Assets and Intangible Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Gross amount	$ 131,910	$ 308,895
Accumulated amortization	(97,749)	(172,114)
Total, net	34,161	136,781
Gross amount	386,512	503,373
Accumulated amortization	(321,152)	(341,779)
Total, net	$ 65,360	$ 161,594