Significant Acquisitions and Other Transactions Significant Acquisitions, Dispositions and Other Agreements - Dispositions (Details) (Global Tower LLC [Member], USD $)	3 Months Ended
Jun. 30, 2011
Global Tower LLC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Sales of Business, Affiliate and Productive Assets	$ 23,890,698

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