Schedule III - Consolidated Financial Statement Schedule of Rental Properties and Accumulated Depreciation Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2017
Rental Properties and Current, Near-Term and Future Value-Creation Projects
Balance at beginning of period	$ 14,181,780		$ 12,178,255	$ 10,632,518
Purchase of real estate	2,240,376		1,057,036	707,522
Additions to real estate	1,143,035		959,410	881,463
Sale of real estate	(12,235)		(12,921)	(43,248)
Balance at end of period	17,552,956	[1]	14,181,780	12,178,255
Accumulated Depreciation
Balance at beginning of period	2,268,087		1,880,236	1,554,546
Depreciation expense on properties	448,661		390,471	348,064
Sale of properties	(7,830)		(2,620)	(22,374)
Balance at end of period	$ 2,708,918	[2]	$ 2,268,087	$ 1,880,236

[1] The aggregate cost of real estate for federal income tax purposes is not materially different from the cost basis under GAAP (unaudited).

[2] The depreciable life ranges up to 40 years for buildings and improvements, up to 20 years for land improvements, and the term of the respective lease for tenant improvements.