Deferred Revenue and Acquisition Related Liabilities, net (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Deferred Revenue Arrangement [Line Items]
Acquisition-related intangible liabilities, net	$ 43,427	[1],[2]	$ 49,776	[1],[2]
Deferred revenue and acquisition-related intangible liabilities, net	132,239		101,286
Tenant Funded Tenant Improvements [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	85,757	[3]	48,341	[3]
Other Deferred Revenue [Member]
Deferred Revenue Arrangement [Line Items]
Deferred Revenue	$ 3,055		$ 3,169

[1] Included in deferred revenue and acquisition-related intangible liabilities, net in the consolidated balance sheets

[2] See Note 2 “Basis of Presentation and Significant Accounting Policies” and Note 4 “Deferred Leasing Costs and Acquisition-related Intangible Assets and Liabilities, net” for additional information.

[3] Excludes deferred revenue related to tenant-funded tenant improvements related to properties held for sale at