Debt Instrument, Debt Default, Accrued Interest Rate.

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- Definition

Interest Rate Used To Account for Mortgage Loan At Fair Value Upon Assumption.

+ Details

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- Definition

The loan balance at the balance sheet date of mortgage debt that was fair valued upon acquisition.

+ Details

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- Definition

Refinancing Of Secured Debt.

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- Definition

Interest rate stated in the contractual debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Date when the debt instrument is scheduled to be fully repaid, which may be presented in a variety of ways (year, month and year, day, month and year, quarter, etc.).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

The carrying amount of the outstanding balance due under the mortgage loan.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section S99

-Paragraph 1

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-Name Regulation S-X (SX)

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-Name Regulation S-X (SX)

-Number 210

-Section 29

-Article 12

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule IV)

-URI http://asc.fasb.org/extlink&oid=6882300&loc=d3e5864-122674

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

The amount of debt that an Entity assumes in acquiring a business or in consideration for an asset received in a noncash (or part noncash) acquisition. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 32

-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.

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- Definition

The net cash inflow or cash outflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity that is collateralized (backed by pledge, mortgage or other lien in the entity's assets).

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- Definition

The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 18

-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.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 20

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-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.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

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

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Mortgage Notes Payable (Details) (USD $)	0 Months Ended		9 Months Ended			0 Months Ended	9 Months Ended	0 Months Ended
Mortgage Notes Payable (Details) (USD $)	Nov. 04, 2011	Nov. 03, 2011	Sep. 30, 2011	Sep. 30, 2010	Jan. 12, 2011 Montvale Center [Member]	Feb. 01, 2011 Bay Colony Corporate Center [Member]	Sep. 30, 2011 Bay Colony Corporate Center [Member]	Aug. 19, 2011 601 Lexington Avenue [Member]	May 11, 2011 601 Lexington Avenue [Member]	Aug. 19, 2011 510 Madison Avenue [Member]
Mortgage Loans on Real Estate [Line Items]
Carrying amount of loan								$ 725,000,000
Interest at a fixed rate	2.875%	3.70%				6.53%		4.75%	7.19%
Debt default, accrued interest rate					9.93%
Maturity date	Feb. 15, 2037	Nov. 15, 2018				Jun. 11, 2012		Apr. 10, 2022	May 11, 2011
Portion of acquisition included in debt						143,900,000	143,900,000
Outstanding balance of mortgage loan accounted for at fair value						149,200,000
Interest rate used to account for mortgage loan at fair value upon assumption						3.75%
Amount of mortgage loan that was repaid			1,196,074,000	301,531,000					453,300,000
Refinancing of secured debt										267,500,000
Repayments of unsecured line of credit			$ 453,300,000					$ 453,300,000