ACQUISITIONS OF REAL ESTATE PROPERTY (Details 2) (USD $)		1 Months Ended
	Mar. 31, 2012	Jul. 31, 2011 NHP property	Jul. 01, 2011 NHP	Jul. 01, 2011 NHP Triple-Net Leased Properties	Jul. 01, 2011 NHP MOB Operations
Business acquisition
Number of properties acquired		643
Fair values of the assets acquired and liabilities assumed at the date of acquisition
Land and improvements			$ 704,499,000
Buildings and improvements			6,216,741,000
Acquired lease intangibles			502,383,000
Investment in unconsolidated entities			93,553,000
Other assets			749,891,000
Total assets acquired			8,267,067,000
Notes payable and other debt			1,882,752,000
Other liabilities			735,951,000
Total liabilities assumed			2,618,703,000
Redeemable OP unitholder interests assumed			100,888,000
Noncontrolling interest assumed			76,657,000
Net assets acquired			5,470,819,000
Cash acquired			29,205,000
Equity issued			5,365,819,000
Total cash used	37,800,000		75,795,000
Goodwill included in other assets			$ 350,000,000	$ 294,900,000	$ 55,100,000