Individually Significant Dispositions - Results of Operations Attributable to Starwood Transaction (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
REVENUES
Rental income	$ 2,470,689	$ 2,422,233	$ 2,736,578
Total revenues	2,471,406	2,425,800	2,744,965
EXPENSES
Property and maintenance	405,281	406,823	479,160
Real estate taxes and insurance	335,495	317,387	339,802
Property management	85,493	82,015	86,206
General and administrative	52,224	57,840	64,664
Depreciation	743,749	705,649	765,895
Total expenses	1,623,935	1,569,714	1,735,727
Operating income	847,471	856,086	1,009,238
Interest and other income	6,136	65,773	7,372
Other expenses	(5,186)	(10,368)	(2,942)
Interest:
Expense incurred, net	(383,890)	(482,246)	(444,487)
Amortization of deferred financing costs	(8,526)	(12,633)	(10,801)
Income and other tax (expense) benefit	(478)	(1,613)	(917)
Net gain (loss) on sales of real estate properties	157,057	4,044,055	335,134
Net Income (Loss) Attributable to Noncontrolling Interest	(22,604)	(171,511)	(34,241)
Net income attributable to controlling interests	$ 603,454	4,292,163	870,120
Starwood Portfolio [Member] | Disposal Group, Not Discontinued Operations [Member]
REVENUES
Rental income		30,785	427,433
Total revenues		30,785	427,433
EXPENSES
Property and maintenance		7,838	78,189
Real estate taxes and insurance		2,912	48,403
Property management		2	11
General and administrative		23	38
Depreciation		0	87,616
Total expenses		10,775	214,257
Operating income		20,010	213,176
Interest and other income		21	1
Other expenses		0	(35)
Interest:
Expense incurred, net		(380)	(680)
Amortization of deferred financing costs		(707)	(559)
Income and other tax (expense) benefit		(1)	(1)
Net gain (loss) on sales of real estate properties		3,161,097	0
Income from operations attributable to controlling interests – Operating Partnership		3,180,040	211,902
Net Income (Loss) Attributable to Noncontrolling Interest		(122,152)	(8,083)
Net income attributable to controlling interests		$ 3,057,888	$ 203,819