Schedule III - Real Estate and Accumulated Depreciation - Summary of Activity for Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Real estate:
Balances at beginning of year	$ 13,137,644	$ 12,592,841	$ 12,524,224
Acquisition of real estate and development and improvements	1,930,931	756,043	257,189
Disposition of real estate	(121,374)	(169,311)	(78,151)
Impairments	(3,118)
Balances associated with changes in reporting presentation	(56,331)	(41,929)	(110,421)
Balances at end of year	14,887,752	13,137,644	12,592,841
Accumulated depreciation:
Balances at beginning of year	2,250,757	1,965,592	1,694,892
Depreciation expense	418,591	384,019	353,344
Disposition of real estate	(17,251)	(55,745)	(38,447)
Balances associated with changes in reporting presentation	(47,061)	(43,109)	(44,197)
Balances at end of year	$ 2,605,036	$ 2,250,757	$ 1,965,592