STOCKHOLDERS' EQUITY (Details) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Issuance of common stock, shares	3,750,202
Issuance of common stock	$ 285,400,000	$ 285,327,000	$ 242,107,000
Sales agent commissions and fees for common stock sales	4,400,000
Common stock reserved for future issuance, amount		1,000,000,000
Accumulated Other Comprehensive Income
Foreign currency translation		(10,006,000)	866,000
Unrealized gain (loss) on marketable debt securities		8,133,000	6,784,000
Other		6,230,000	5,471,000
Total accumulated other comprehensive income		4,357,000	13,121,000
Common Stock
Business Acquisition [Line Items]
Issuance of common stock		$ 938,000	$ 845,000
American Realty Capital Healthcare Trust | Common Stock
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares	28,400,000
American Realty Capital Healthcare Trust | Limited Partnership Units
Business Acquisition [Line Items]
Business acquisition, equity interest issued, number of shares	1,100,000