Schedule III - Real Estate and Accumulated Depreciation - Changes in Real Estate Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Balance, beginning of period	$ 11,568,809,126	$ 10,018,225,775	$ 9,123,343,869
Acquisitions	181,719,189	278,401,182	548,553,619
Improvements	217,668,292	191,662,698	134,921,993
Transfers from (to) unconsolidated joint ventures	615,511,560	1,673,542,610	1,065,330,540
Sales	(391,758,149)	(507,185,370)	(781,200,981)
Assets held for sale	(12,608,829)	(587,007)
Adjustment of fully depreciated asset	(80,660,536)	(56,774,522)	(8,628,954)
Adjustment of property carrying values	(91,204,249)	(18,432,226)	(32,935,408)
Change in exchange rate	598,744	(10,044,014)	(31,158,903)
Balance, end of period	12,008,075,148	11,568,809,126	10,018,225,775
Balance, beginning of period	2,115,319,888	1,955,405,720	1,878,680,836
Depreciation for year	344,179,201	333,948,605	256,088,382
Transfers from (to) unconsolidated joint ventures
Sales	(97,063,934)	(116,864,875)	(167,458,882)
Adjustment of fully depreciated asset	(80,660,536)	(56,774,522)	(8,628,954)
Assets held for sale	(3,482,974)
Change in exchange rate		(395,040)	(3,275,662)
Balance, end of period	$ 2,278,291,645	$ 2,115,319,888	$ 1,955,405,720