Intangible Assets and Liability (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Intangible Assets and Liabilities
Intangible assets gross	$ 40,933	$ 40,933
Less: accumulated amortization	(1,401)	(951)
Intangible assets, net	39,532	39,982
Unfavorable contract liability	14,236	14,236
Less: accumulated amortization	(392)	(98)
Intangible liability, net (included within other liabilities)	13,844	14,138
Air Rights Contract [Member]
Intangible Assets and Liabilities
Intangible assets gross	36,105	36,105
Favorable Ground Leases [Member]
Intangible Assets and Liabilities
Intangible assets gross	$ 4,828	$ 4,828

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph ((a)(1),(b))

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 42, 45

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_IntangibleAssetsNetExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant