SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate Properties
Balance at the beginning of the year	$ 7,829,409,000	$ 7,244,232,000	$ 6,357,258,000
Additions	231,485,000	1,041,655,000	1,074,010,000
Loss on asset impairment	(384,141,000)	(242,497,000)
Deconsolidation of SIR	(1,446,781,000)
Properties reclassified to discontinued operations	(552,024,000)	(174,562,000)	42,228,000
Disposals	(140,783,000)	(39,419,000)	(229,264,000)
Balance at the end of the year	5,537,165,000	7,829,409,000	7,244,232,000
Accumulated Depreciation
Balance at the beginning of the year	1,007,606,000	934,170,000	850,261,000
Additions	176,777,000	188,220,000	166,371,000
Loss on asset impairment	(185,795,000)	(73,865,000)
Deconsolidation of SIR	(56,023,000)
Properties reclassified to discontinued operations	(15,471,000)	(10,521,000)	3,083,000
Disposals	(32,035,000)	(30,398,000)	(85,545,000)
Balance at the end of the year	895,059,000	1,007,606,000	934,170,000
REAL ESTATE AND ACCUMULATED DEPRECIATION
Aggregate cost of properties for federal income tax purposes	5,642,335,000
Real estate properties additions due to changes in foreign currency exchange	40,020,000	4,986,000	(333,000)
Accumulated depreciation additions due to changes in foreign currency exchange	$ (1,528,000)	$ 97,000	$ (73,000)
Buildings and improvements | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives	40 years
Personal property | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives	12 years