Schedule III - Real Estate and Accumulated Depreciation (Changes in Total Real Estate Assets and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule III - Real Estate and Accumulated Depreciation [Abstract]
Balance, beginning of period	$ 8,328,475	$ 7,667,743	$ 7,376,690
Acquisition of operating properties and unconsolidated joint ventures	422,309	286,901	56,985
Development and repositions	341,236	300,294	224,202
Improvements	75,360	84,841	71,889
Cost of real estate sold – other	(51,587)	(11,304)	(62,023)
Balance, end of period	9,115,793	8,328,475	7,667,743
Balance, Beginning of period	2,403,149	2,118,839	1,890,656
Depreciation of real estate assets	317,026	284,310	255,924
Dispositions	(34,150)	0	(27,741)
Balance, End of period	2,686,025	$ 2,403,149	$ 2,118,839
Real Estate, Federal Income Tax Basis	$ 8,200,000