ACQUISITIONS (Details 2) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
2015 Acquisitions
Business Acquisition [Line Items]
Land and improvements	$ 332,955,000
Buildings and improvements	2,379,200,000
Acquired lease intangibles	279,921,000
Other assets	734,274,000
Total assets acquired	3,726,350,000
Notes payable and other debt	177,857,000
Other liabilities	117,640,000
Total liabilities assumed	295,497,000
Net assets acquired	3,430,853,000
Noncontrolling interest assumed	87,244,000
Cash acquired	54,716,000
Equity issued	2,216,355,000
Total cash used	1,072,538,000
Goodwill	665,800,000
2015 Acquisitions | Triple-Net Leased Properties
Business Acquisition [Line Items]
Land and improvements	91,559,000
Buildings and improvements	637,136,000
Acquired lease intangibles	28,334,000
Other assets	127,790,000
Total assets acquired	884,819,000
Other liabilities	28,738,000
Total liabilities assumed	28,738,000
Net assets acquired	856,081,000
Goodwill	117,800,000
2015 Acquisitions | Senior Living Operations
Business Acquisition [Line Items]
Land and improvements	70,713,000
Buildings and improvements	703,080,000
Acquired lease intangibles	83,867,000
Other assets	271,823,000
Total assets acquired	1,129,483,000
Notes payable and other debt	77,940,000
Other liabilities	44,499,000
Total liabilities assumed	122,439,000
Net assets acquired	1,007,044,000
Goodwill	217,800,000
2015 Acquisitions | MOB Operations
Business Acquisition [Line Items]
Land and improvements	170,683,000
Buildings and improvements	1,038,984,000
Acquired lease intangibles	167,720,000
Other assets	334,661,000
Total assets acquired	1,712,048,000
Notes payable and other debt	99,917,000
Other liabilities	44,403,000
Total liabilities assumed	144,320,000
Net assets acquired	1,567,728,000
Goodwill	330,200,000
2014 Acquisitions
Business Acquisition [Line Items]
Land and improvements		145,867,000
Buildings and improvements		1,628,233,000
Acquired lease intangibles		65,335,000
Other assets		12,620,000
Total assets acquired		1,852,055,000
Notes payable and other debt		241,077,000
Other liabilities		133,323,000
Total liabilities assumed		374,400,000
Net assets acquired		1,477,655,000
Cash acquired		8,931,000
Total cash used		1,468,724,000
2014 Acquisitions | Triple-Net Leased Properties
Business Acquisition [Line Items]
Land and improvements		45,586,000
Buildings and improvements		546,849,000
Acquired lease intangibles		28,883,000
Other assets		227,000
Total assets acquired		621,545,000
Notes payable and other debt		12,927,000
Other liabilities		8,609,000
Total liabilities assumed		21,536,000
Net assets acquired		600,009,000
Cash acquired		227,000
Total cash used		599,782,000
2014 Acquisitions | Senior Living Operations
Business Acquisition [Line Items]
Land and improvements		100,281,000
Buildings and improvements		1,081,384,000
Acquired lease intangibles		36,452,000
Other assets		12,393,000
Total assets acquired		1,230,510,000
Notes payable and other debt		228,150,000
Other liabilities		124,714,000
Total liabilities assumed		352,864,000
Net assets acquired		877,646,000
Cash acquired		8,704,000
Total cash used		$ 868,942,000