Real Property Acquisitions and Development (Details 1) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011
Senior housing - triple net [Member]
Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities
Land and land improvements	$ 29,320	[1]	$ 179,321
Buildings and improvements	394,508	[1]	2,670,282
Acquired lease intangibles	0	[1]	0
Restricted cash	0	[1]	0
Investment in unconsolidated entities	0	[1]	0
Receivables and other assets	0	[1]	0
Cash and cash equivalents	0	[1]	0
Total assets acquired	423,828	[1]	2,849,603
Assumed debt	(56,337)	[1]	(93,425)
Accrued expenses and other liabilities	(1,568)	[1]	(75,144)
Total liabilities assumed	(57,905)	[1]	(168,569)
Capital in excess of par	1,024	[1]	0
Noncontrolling interests	(15,820)	[1]	0
Cash disbursed for acquisitions	350,817	[1]	2,681,034
Construction in progress additions	81,419	[1]	75,999
Less: Capitalized Interest	(2,629)	[1]	(2,331)
Cash disbursed for construction in progress	78,790	[1]	73,668
Capital improvements to existing properties	36,421	[1]	11,556
Non-cash acquisition related activity	(310)	[1]	0
Total cash invested in real property	466,028	[1]	2,766,258
Senior housing - operating [Member]
Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities
Land and land improvements	27,647		71,610
Buildings and improvements	241,287		966,235
Acquired lease intangibles	24,052		88,285
Restricted cash	0		5,451
Investment in unconsolidated entities	0		0
Receivables and other assets	1,182		14,960
Total assets acquired	294,168	[2]	1,146,541
Assumed debt	(8,684)		(585,656)
Accrued expenses and other liabilities	(1,665)		(30,681)
Total liabilities assumed	(10,349)		(616,337)
Capital in excess of par	0		(6,017)
Noncontrolling interests	(2,054)		(27,411)
Cash disbursed for acquisitions	281,765		468,686
Capital improvements to existing properties	8,553		7,661
Non-cash acquisition related activity	0		(28,090)
Total cash invested in real property	290,318		476,347
Cash Acquired from Acquisition	1,619		34,342
Medical facilities [Member]
Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities
Land and land improvements	30,160	[3]	7,711
Buildings and improvements	489,659	[3]	63,532
Acquired lease intangibles	58,998	[3]	1,126
Restricted cash	975	[3]	0
Receivables and other assets	4,250	[3]	0
Total assets acquired	584,042	[3]	72,369
Assumed debt	(238,589)	[3]	(42,551)
Accrued expenses and other liabilities	(12,775)	[3]	(568)
Total liabilities assumed	(251,364)	[3]	(43,119)
Cash disbursed for acquisitions	331,798	[3]	29,250
Construction in progress additions	64,937	[3]	124,150
Less: Capitalized Interest	(1,929)	[3]	(4,648)
Less: Accruals	(10,911)	[3],[4]	(30,736)	[4]
Cash disbursed for construction in progress	52,097	[3]	88,766
Capital improvements to existing properties	18,025	[3]	9,976
Non-cash acquisition related activity	(880)	[3]	0
Total cash invested in real property	401,920	[3]	127,992
Total purchase price	$ 545,824

[1] (1) Includes acquisitions with an aggregate purchase price of $129,545,000 for which the allocation of the purchase price consideration is preliminary and subject to change.

[2] (1) Excludes $1,619,000 and $34,342,000 of cash acquired during the six months ended June 30, 2012 and 2011, respectively.

[3] (2) Includes acquisitions with an aggregate purchase price of $545,824,000 for which the allocation of the purchase price consideration is preliminary and subject to change.

[4] (1) Represents non-cash accruals for amounts to be paid in future periods relating to properties that converted in the periods noted above.