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Summary of Significant Accounting Policies (Details 2) | 12 Months Ended
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Dec. 31, 2011 form
Share-Based Compensation |
Forms of share-based compensation issued in 2010 and 2011 | 2
Market concentration premium |
Intangible assets and deferred revenue on real estate acquisitions |
Period during which intangible assets will be amortized (in years) | 40

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- Definition Represents the number of forms of awards issued under the share-based compensation plan. + References No definition available. + Details
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- Definition The useful life of all finite-lived intangible assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 12, 13, 14 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 35 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15372-109273 + Details
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