Intangible Assets and Intangible Liabilities - Summary of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Intangible assets:
Gross amount	$ 503,333		$ 503,333		$ 515,889
Accumulated amortization	(264,007)		(264,007)		(245,444)
Intangible assets, Net	239,326		239,326		270,445
Intangible liabilities:
Gross amount	179,430		179,430		185,191
Accumulated amortization	(94,899)		(94,899)		(89,200)
Intangible Liabilities, Net	84,531		84,531		$ 95,991
Amortization of above and below-market leases, net			(6,003)	$ (8,724)
Leases, Acquired-in-Place, Market Adjustment [Member]
Intangible liabilities:
Amortization of above and below-market leases, net	(2,727)	$ (4,304)	(6,003)	(8,724)
Leases, Acquired-in-Place [Member]
Intangible liabilities:
Amortization of acquired in-place leases (component of "depreciation and amortization")	$ 12,330	$ 14,721	$ 25,663	$ 30,014