STOCKHOLDERS' EQUITY - Capital Stock (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended
	Jul. 29, 2016	Jun. 30, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Issuance of common stock, shares		6,116,189
Proceeds for the issuance of common stock		$ 378,100
Sales agent commissions for common stock sales		5,800
Equity offering program, remaining authorized offering amount		406,800
Conversion of stock, value redeemed		20,800
Issuance of common stock		$ 377,739	$ 491,024
Common Stock
Business Acquisition [Line Items]
Conversion of stock, number of Ventas shares issued		340,845
Issuance of common stock		$ 1,529	$ 1,797
Ventas Realty OP Units
Business Acquisition [Line Items]
Partners' capital account, units, redeemed (in shares)		32,747
Class C Units
Business Acquisition [Line Items]
Partners' capital account, units, redeemed (in shares)		311,208
Subsequent Event
Business Acquisition [Line Items]
Public offering sale, common shares (in shares)	10,260,434
Issuance of common stock	$ 735,800