STOCKHOLDERS' EQUITY - Capital Stock (Details) - USD ($) $ in Millions |
1 Months Ended | 9 Months Ended |
|---|---|---|
Oct. 28, 2016 |
Sep. 30, 2016 |
|
| Business Acquisition [Line Items] | ||
| Issuance of common stock, shares | 18,566,822 | |
| Proceeds for the issuance of common stock | $ 1,300.0 | |
| Equity offering program, remaining authorized offering amount | 252.1 | |
| Conversion of stock, value redeemed | $ 23.0 | |
| Common Stock | ||
| Business Acquisition [Line Items] | ||
| Conversion of stock, number of Ventas shares issued | 370,558 | |
| Ventas Realty OP Units | ||
| Business Acquisition [Line Items] | ||
| Partners' capital account, units, redeemed (in shares) | 65,581 | |
| Class C Units | ||
| Business Acquisition [Line Items] | ||
| Partners' capital account, units, redeemed (in shares) | 311,208 | |
| Subsequent Event | ||
| Business Acquisition [Line Items] | ||
| Issuance of common stock, shares | 297,019 | |
| Proceeds for the issuance of common stock | $ 21.2 | |
| Sales agent commissions for common stock sales | $ 0.3 |