Related Party Transactions Repayment of Loans to Property Owning Entities (Details) (500 Mamaroneck Avenue [Member], USD $) In Millions, unless otherwise specified	0 Months Ended
Apr. 21, 2011
Investor [Member]
Related Party Transaction [Line Items]
Repayment of notes from related parties	$ 3.6
Anthony E. and Peter L. Malkin [Member]
Related Party Transaction [Line Items]
Repayment of notes from related parties	1.2
Anthony E. and Peter L. Malkin Interests Held [Member]
Related Party Transaction [Line Items]
Notes payable to related party assumed	$ 3.8

The cash inflow from a loan, supported by a promissory note, granted to related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

Name:	us-gaap_RepaymentOfNotesReceivableFromRelatedParties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration