STOCKHOLDERS' EQUITY - Capital Stock (Details) shares in Millions, $ in Millions |
6 Months Ended |
|---|---|
|
Jun. 30, 2017
USD ($)
shares
| |
| Equity [Abstract] | |
| Issuance of common staock, shares | shares | 1.1 |
| Proceeds from issuance of common stock | $ 73.9 |
| Equity offering program, remaining authorized offering amount | $ 155.6 |