SEC Schedule III Rollforward of Real Estate Assets and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]
Real estate, balance at beginning of period	$ 16,237,883	$ 14,756,295	$ 14,187,820
Additions during the period	17,675,741	16,592,044	14,807,938
Less: Assets sold, written-off and deconsolidated	4,601,729	354,161	51,643
Real estate, balance at end of period	13,074,012	16,237,883	14,756,295
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Accumulated Depreciation [Roll Forward]
Accumulated depreciation, balance at beginning of period	3,180,175	2,885,283	2,581,514
Additions charged to operating expenses	360,194	381,500	360,391
Real estate accumulated depreciation	3,540,369	3,266,783	2,941,905
Less: Accumulated depreciation on assets sold, written-off and deconsolidated	524,411	86,608	56,622
Accumulated depreciation, balance at end of period	3,015,958	3,180,175	2,885,283
Land
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]
Additions during the period	46,074	170,065	21,298
Buildings & improvements
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate [Roll Forward]
Additions during the period	$ 1,391,784	$ 1,665,684	$ 598,820