Acquisitions Acquisitions - Schedule of allocation of the purchase price for assets and liabilities acquired (Details) (Subsequent Event [Member], USD $) In Thousands, unless otherwise specified	0 Months Ended
	Jul. 15, 2014	Jul. 15, 2014
Subsequent Event [Member]
Consideration paid:
Cash and issuance of Class A Common Stock, Class B Common Stock, and Series PR OP units	$ 565,916
Debt assumed	167,684
Total consideration paid	733,600
Net assets acquired:
Land and building and improvements		439,965
Acquired below-market ground lease		261,899
Acquired above-market leases		24,133
Acquired in place lease value and deferred leasing costs		64,473
Mortgage notes payable		(183,401)
Acquired below-market leases		(41,153)
Total net assets acquired		$ 565,916