Intangible Assets and Intangible Liabilities - Summary of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Intangible assets:
Gross amount	$ 487,511		$ 487,511		$ 515,889
Accumulated amortization	(264,802)		(264,802)		(245,444)
Intangible assets, Net	222,709		222,709		270,445
Intangible liabilities:
Gross amount	177,665		177,665		185,191
Accumulated amortization	(98,829)		(98,829)		(89,200)
Intangible Liabilities, Net	78,836		78,836		$ 95,991
Amortization of above and below-market leases, net			(8,555)	$ (12,611)
Leases, Acquired-in-Place, Market Adjustment [Member]
Intangible liabilities:
Amortization of above and below-market leases, net	(2,552)	$ (3,887)	(8,555)	(12,611)
Leases, Acquired-in-Place [Member]
Intangible liabilities:
Amortization of acquired in-place leases (component of "depreciation and amortization")	$ 11,917	$ 14,865	$ 37,580	$ 44,879