Schedule III - Real Estate and Accumulated Depreciation - Changes in Real Estate Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Balance, beginning of period	$ 12,653,444,998	$ 12,008,075,148	$ 11,568,809,126
Acquisitions	3,420,020	438,125,265	181,719,189
Improvements	554,408,568	414,955,609	217,668,292
Transfers from unconsolidated joint ventures		329,194,717	615,511,560
Change in exchange rate		1,035,816	598,744
Sales	(767,246,512)	(315,954,464)	(391,758,149)
Transfers to unconsolidated joint ventures	(315,728,832)
Assets held for sale	(69,741,938)	(56,187,719)	(12,608,829)
Adjustment for fully depreciated assets	(72,992,791)	(107,660,366)	(80,660,536)
Adjustment of property carrying values	(108,373,018)	(58,139,008)	(91,204,249)
Balance, end of period	$ 11,877,190,495	$ 12,653,444,998	$ 12,008,075,148