STOCKHOLDERS' EQUITY - Capital Stock (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Apr. 29, 2016	Mar. 31, 2016	Mar. 31, 2016
Business Acquisition [Line Items]
Issuance of common stock, shares			2,621,729
Proceeds for the issuance of common stock			$ 149.9
Sales agent commissions for common stock sales			2.3
Equity Offering Program, Remaining Authorized Offering Amount		$ 638.5	$ 638.5
Conversion of stock, value redeemed		$ 18.6
Common Stock
Business Acquisition [Line Items]
Conversion of Stock, number of Ventas shares issued		305,047
Class C Units
Business Acquisition [Line Items]
Partners' capital account, units, redeemed (in shares)		305,047
Subsequent Event
Business Acquisition [Line Items]
Issuance of common stock, shares	641,466
Proceeds for the issuance of common stock	$ 39.9
Sales agent commissions for common stock sales	$ 0.6