SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2012 property lease	Dec. 31, 2011 property	Dec. 31, 2010 property
Reconciliation of total real estate carrying value
Balance at Beginning of Period	$ 4,976,096,132	$ 4,119,901,302	$ 3,449,776,818
Acquisitions	1,130,059,158	1,016,170,863	713,534,296
Less amounts allocated to intangible assets that are included in Other Assets on our Consolidated Balance Sheets	(86,100,036)	(133,491,909)	(15,384,932)
Equipment	0	14,238	33,268
Improvements, Etc.	4,934,558	2,435,950	2,044,036
Other (Leasing Costs and Building Adjustments as a result of net debt premiums)	13,081,252	3,286,251	1,500,953
Total Additions	1,061,974,932	888,415,393	701,727,621
Cost of Real Estate sold or disposed of	54,223,955	31,383,561	30,254,678
Cost of Equipment sold	0	0	0
Releasing costs	582,705	584,192	410,234
Other (including Provisions for Impairment)	5,108,475	252,810	938,225
Total Deductions	59,915,135	32,220,563	31,603,137
Balance at Close of Period	5,978,155,929	4,976,096,132	4,119,901,302
Reconciliation of accumulated depreciation for the years ended:
Balance at Beginning of Period	816,087,890	715,023,381	632,894,759
Additions During Period - Provision for Depreciation	135,470,091	113,671,104	94,489,028
Deductions During Period: Accumulated depreciation of real estate and equipment sold or disposed of	15,538,907	12,606,595	12,360,406
Balance at Close of Period	936,019,074	816,087,890	715,023,381
Number of properties on which provisions for impairment were recorded	10	5	4
Adjustments to estimated legal obligations related to asset retirement obligations	$ 30,553	$ 152,277	$ 81,593
Number of land leases with adjustments recorded to estimated legal obligations related to asset retirement obligations	2