Acquisitions of Real Estate Property (Details Textuals) (USD $) | 3 Months Ended | 9 Months Ended | 1 Months Ended | 1 Months Ended | 1 Months Ended | 1 Months Ended | 1 Months Ended | 9 Months Ended | 3 Months Ended | 9 Months Ended | 1 Months Ended | 3 Months Ended | 9 Months Ended | 1 Months Ended | 9 Months Ended | |||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | Dec. 31, 2010 | Jun. 30, 2010
96 MOBs [Member]
Lillibridge Acquisition [Member]
Building | Jul. 02, 2010
96 MOBs [Member]
Lillibridge Acquisition [Member] | Jun. 30, 2010
38 MOBs [Member]
Building | Jul. 02, 2010
38 MOBs [Member]
Lillibridge Acquisition [Member] | Jun. 30, 2010
24 MOBs [Member]
Building | Jul. 02, 2010
24 MOBs [Member]
Lillibridge Acquisition [Member] | Jun. 30, 2010
34 MOBs [Member]
Building | Jul. 02, 2010
34 MOBs [Member]
Lillibridge Acquisition [Member] | Dec. 31, 2010
5 MOBs [Member]
Building | Oct. 31, 2011
2 MOBs [Member]
Other Acquisition [Member]
Property | Sep. 30, 2011
Nationwide Health Properties [Member]
Triple-Net Leased Properties [Member] | Sep. 30, 2011
Nationwide Health Properties [Member]
Operating Assets [Member] | Sep. 30, 2011
Atria Senior Living Acquisition [Member] | Sep. 30, 2011
Atria Senior Living Acquisition [Member] | May 12, 2011
Atria Senior Living Acquisition [Member]
Property | Jul. 02, 2010
Lillibridge Acquisition [Member]
Party | Dec. 31, 2010
Minimum [Member]
Sunrise Acquisition [Member] | Dec. 31, 2010
Maximum [Member]
Sunrise Acquisition [Member] | Dec. 31, 2010
Sunrise Acquisition [Member]
Property | Sep. 30, 2011
Nationwide Health Properties [Member] | Sep. 30, 2011
Nationwide Health Properties [Member]
Property
HousingCommunity | Jul. 02, 2011
Nationwide Health Properties [Member] | Oct. 31, 2011
Other Acquisition [Member]
Property | Aug. 31, 2011
Other Acquisition [Member]
Property | Sep. 30, 2011
Other Acquisition [Member]
Property | Aug. 02, 2011
Seniors Housing Asset [Member] | Oct. 31, 2011
MOBs and Senior housing communities [Member] | |
| Acquisitions of Real Estate Property (Textuals) [Abstract] | ||||||||||||||||||||||||||||||||
| Purchase price of acquisition of assets | $ 381,000,000 | $ 186,000,000 | ||||||||||||||||||||||||||||||
| Purchase price of seniors housing asset | 3,594,802,000 | 3,594,802,000 | 8,318,678,000 | 8,318,678,000 | 3,800,000 | 150,300,000 | ||||||||||||||||||||||||||
| Value of common stock shares issued related to acquisition | 1,380,000,000 | 5,400,000,000 | ||||||||||||||||||||||||||||||
| Business acquisition equity interests issued or issuable number of shares issued | 24,960,000 | |||||||||||||||||||||||||||||||
| Business acquisition equity interest issued or issuable per share | $ 55.33 | $ 53.74 | ||||||||||||||||||||||||||||||
| Total number of private pay seniors housing communities through acquisition | 117 | |||||||||||||||||||||||||||||||
| Revenues From Properties Acquired | 157,100,000 | 242,800,000 | 134,800,000 | 134,800,000 | ||||||||||||||||||||||||||||
| NOI from properties acquired | 47,500,000 | 73,700,000 | 122,900,000 | 122,900,000 | ||||||||||||||||||||||||||||
| Assumption of mortgage debt | 79,500,000 | 144,000,000 | 37,700,000 | |||||||||||||||||||||||||||||
| Acquired Ownership Interest | 100.00% | 20.00% | 5.00% | |||||||||||||||||||||||||||||
| Acquired ownership interest in Lillibridge's services and development business | 100.00% | |||||||||||||||||||||||||||||||
| Number of institutional third parties holding majority interests of joint ventures | 2 | |||||||||||||||||||||||||||||||
| Repaid mortgage debt involved in acquisition | 132,700,000 | |||||||||||||||||||||||||||||||
| Acquired ownership interest in seventy nine seniors housing communities | 100.00% | |||||||||||||||||||||||||||||||
| Number of acquisitions involved in Sunrise's noncontrolling interests | 58 | |||||||||||||||||||||||||||||||
| Number of seniors housing communities involved with Sunrise | 79 | 2 | 1 | |||||||||||||||||||||||||||||
| Noncontrolling interests acquired represent Seventy Nine Seniors Housing Communities | 15.00% | 25.00% | ||||||||||||||||||||||||||||||
| Purchase price of 5 MOBs | 36,600,000 | |||||||||||||||||||||||||||||||
| Acquisition related costs | 69,350,000 | 5,142,000 | 131,606,000 | 11,668,000 | 1,500,000 | 48,200,000 | 42,500,000 | 54,800,000 | ||||||||||||||||||||||||
| Total acquisition related cost | 52,500,000 | 52,500,000 | 54,800,000 | 54,800,000 | ||||||||||||||||||||||||||||
| Number of Medical office buildings purchased | 2 | |||||||||||||||||||||||||||||||
| Number of properties acquired | 96 | 38 | 24 | 34 | 5 | 643 | ||||||||||||||||||||||||||
| Contingent consideration liability, Fair Value | 56,218,000 | 56,218,000 | 0 | 44,200,000 | 44,200,000 | 44,200,000 | ||||||||||||||||||||||||||
| Conversion ratio of acquired entity common stock to parent common stock | 0.7866 | |||||||||||||||||||||||||||||||
| Goodwill | 79,200,000 | 79,200,000 | 189,600,000 | 189,600,000 | ||||||||||||||||||||||||||||
| Deferred tax liability | 43,889,000 | 43,889,000 | ||||||||||||||||||||||||||||||
| Amount paid for closing of revolving credit facility | 105,000,000 | |||||||||||||||||||||||||||||||
| Allocation of goodwill | $ 129,400,000 | $ 60,200,000 | ||||||||||||||||||||||||||||||
| Number of shares reduced for working capital adjustment | 83,441 | |||||||||||||||||||||||||||||||
| Number of acquired seniors housing operating asset managed by other | 1 | |||||||||||||||||||||||||||||||