Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011 sqft Segment Y Property D	Sep. 30, 2010
Income Taxes
Maximum ownership as a percentage of the voting power or value of the securities of each issuer other than REIT or "TRS" (as a percent)			10.00%
Maximum ownership of securities in all TRS (as a percent)			25.00%
Maximum ownership of securities in all TRS when considered together with other non-real estate assets (as a percent)			25.00%
Period of statute of limitations applicable to the entity's income tax returns (in years)			3
Federal income tax expense (benefit) at statutory rate			$ 20	$ (526)
Increase (decrease) in taxes resulting from:
State income tax (benefit), net of federal impact				(96)
Valuation allowance on tax expense (benefit)			(17)	360
Revised Texas franchise tax			182	161
Income tax expense (benefit)	$ 67	$ (37)	$ 185	$ (101)
Revised Texas Franchise tax rate (as a percent)			0.70%

Represents the Revised Texas Franchise Tax rate as a percentage of revenues at Texas properties commencing with 2007 revenues.

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The portion of the difference between total income tax expense or benefit as reported in the income statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to the Revised Texas Franchise Tax.

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- Definition

Represents the maximum ownership in all Taxable REIT Subsidiaries that can be held by the entity as a percentage of its assets value to maintain its REIT status.

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Represents the maximum ownership in all Taxable REIT Subsidiaries that can be held by the entity as a percentage of its assets value when considered together with other non-real estate assets to maintain its REIT status.

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- Definition

Represents the maximum ownership that the entity can hold as a percentage of the voting power or value of the securities of each issuer which is not a REIT or Taxable REIT Subsidiary.

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- Definition

Represents the period of statute of limitations for the entity's income tax returns, that remain subject to examination.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to changes in the valuation allowance for deferred tax assets in the period.

+ References

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to state and local income tax expense or benefit.

+ References

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