Deferred Costs, Acquired Lease Intangibles and Goodwill - Deferred Costs, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Leasing costs	$ 165,809	$ 164,751
Total deferred costs, gross amount	450,012	469,530
Less: accumulated amortization	(210,528)	(215,102)
Total deferred costs, net, excluding net deferred financing costs	239,484	254,428
Acquired in-place lease value and deferred leasing costs
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets	223,711	237,364
Acquired above-market leases
Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible assets	$ 60,492	$ 67,415