SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Real Estate Properties
Balance at the beginning of the year	$ 7,244,232	$ 6,357,258	$ 6,323,681
Additions	1,041,655	1,074,010	876,363
Loss on asset impairment	(242,497)		(139,673)
Properties reclassified to discontinued operations	(174,562)	42,228	(138,418)
Disposals	(39,419)	(229,264)	(564,695)
Balance at the end of the year	7,829,409	7,244,232	6,357,258
Accumulated Depreciation
Balance at the beginning of the year	934,170	850,261	884,421
Additions	188,220	166,371	180,631
Loss on asset impairment	(73,865)		(10,458)
Properties reclassified to discontinued operations	(10,521)	3,083	(41,319)
Disposals	(30,398)	(85,545)	(163,014)
Balance at the end of the year	1,007,606	934,170	850,261
REAL ESTATE AND ACCUMULATED DEPRECIATION
Aggregate cost of properties for federal income tax purposes	8,940,479
Real estate property additions due to changes in foreign currency exchange	4,986	(333)	8,387
Accumulated depreciation additions due to changes in foreign currency exchange	97	(73)	12
Impairment charges for real estate properties, continuing operations	$ 10,355
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