SCHEDULE III—REAL ESTATE AND ACCUMULATED DEPRECIATION - Notes to Schedule III (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in total cost of properties
Balance at beginning of year	$ 10,716,233	$ 8,820,346	$ 8,778,907
Additions: acquisitions and capital expenditures	99,141	1,983,380	324,227
Dispositions	(145,836)	0	(62,923)
Reclassification of properties held for sale	(38,978)	(87,493)	(219,865)
Balance at close of year	10,644,000	10,716,233	8,820,346
Change in accumulated depreciation
Balance at beginning of year	2,851,121	2,574,297	2,409,416
Additions: depreciation expense	364,636	305,441	304,224
Dispositions	(143,814)	(28,617)	(62,923)
Reclassification of properties held for sale	(24,927)	0	(76,420)
Balance at close of year	3,047,016	2,851,121	2,574,297
Tax basis for federal income tax purpose	8,316,892
All Properties Excluding Properties Held For Sale
Change in total cost of properties
Balance at beginning of year	10,716,233	8,820,346
Balance at close of year	$ 10,630,560	$ 10,716,233	$ 8,820,346