Fair Value of Financial Instruments (Details) (USD $)	6 Months Ended	12 Months Ended
Jun. 30, 2012	Dec. 31, 2011
Available-for-sale securities
Total cost of available-for-sale securities	$ 153,000
Unrealized gain on available-for-sale securities	128,000
Unrealized losses on available-for-sale securities	1,000
Aggregate net unrealized gain on available-for-sale securities	127,000
Net realized gain on available-for-sale securities	9,000
Impairment charge on available-for-sale securities		126,000
Carrying and fair Value
Available-for-sale securities:
Equity securities	280,000
Financial liabilities:
Derivative financial instruments	1,335,000
Level 1
Available-for-sale securities:
Equity securities	280,000
Level 2
Financial liabilities:
Derivative financial instruments	1,335,000
Mortgages and loan payable
Fair Value of Financial Instruments
Estimated fair value of debt instrument	218,000,000
Excess of fair value over carrying value	8,193,000
Blended or estimated market interest rate (as a percent)	4.50%
Weighted average remaining term of the mortgages	4 years 9 months 18 days
Mortgages payable - property held for sale
Fair Value of Financial Instruments
Estimated fair value of debt instrument	7,266,000
Excess of fair value over carrying value	343,000
Blended or estimated market interest rate (as a percent)	4.50%
Weighted average remaining term of the mortgages	2 years 9 months 18 days
Line of credit
Fair Value of Financial Instruments
Estimated fair value of debt instrument	19,798,000
Excess of fair value over carrying value	$ 198,000
Blended or estimated market interest rate (as a percent)	4.75%

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This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of equity securities categorized neither as held-to-maturity nor as trading.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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