Investments In Unconsolidated Joint Ventures (Red Bank Corporate Plaza) (Narrative) (Details) (Red Bank Corporate Plaza, L.L.C. [Member], USD $)	12 Months Ended
Dec. 31, 2012 sqft	Dec. 31, 2011	Dec. 31, 2010
Red Bank Corporate Plaza, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Area of property (in square feet)	92,878
Lease expiration date	Sep. 30, 2017
Percentage of interest in venture	50.00%
Mortgage loans, carrying amount	$ 17,400,000
Spread over LIBOR	3.00%
Mortgage loan, maturity date	May 2016
LIBOR Interest Rate	0.21%
Percentage of loan that has a fixed interest rate	75.00%
Fixed interest rate	3.99375%
Management, leasing and other services fees	$ 99,000	$ 100,000	$ 91,000

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Management Leasing And Other Services Fees.

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Area of a real estate property.

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The percentage points added to the reference rate to compute the variable rate on the debt instrument.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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-Name Statement of Financial Accounting Standard (FAS)

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-Paragraph 18

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Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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

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