Deferred Costs, Acquired Lease Intangibles and Goodwill - Acquired Leases (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired below-market ground lease, Gross Amount	$ 395,784	$ 62,738
Acquired below-market ground lease, Accumulated Amortization	(3,028)	(426)
Acquired below-market leases, Gross Amount	(170,964)	(134,651)
Acquired below-market leases, Accumulated Amortization	22,471	4,769
Acquired in-place lease value and deferred leasing costs [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	273,187	186,415
Finite-lived intangible assets, Accumulated Amortization	(34,134)	(5,697)
Acquired above-market leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Gross Amount	85,116	72,123
Finite-lived intangible assets, Accumulated Amortization	$ (12,168)	$ (2,858)