Acquisitions - Schedule of allocation of the purchase price for assets and liabilities acquired (Details) $ in Thousands	Jul. 15, 2014 USD ($)
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	354,429
Acquired below-market ground leases	334,178
Acquired above-market leases	13,088
Acquired in place lease value and deferred leasing costs	88,374
Mortgage notes payable, inclusive of premium	(182,851)
Acquired below-market leases	(36,553)
Other liabilities, net of other assets	(4,749)
Total net assets acquired	$ 565,916