CONTRIBUTING EMPLOYEE OWNERSHIP PLAN (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2017 |
Sep. 30, 2016 |
Sep. 30, 2017 |
Sep. 30, 2016 |
|
| Defined Contribution Plan Disclosure [Line Items] | ||||
| Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 7.0 | $ 7.1 | $ 22.4 | $ 20.5 |
| Employer matching contributions to employee ownership plan | $ 3.0 | $ 3.0 | $ 8.7 | $ 8.7 |
| Minimum | ||||
| Defined Contribution Plan Disclosure [Line Items] | ||||
| Contribution To Individual Retirement Account Percentage Of Employees Eligible Compensation | 5.00% | 5.00% | ||
| Maximum | ||||
| Defined Contribution Plan Disclosure [Line Items] | ||||
| Contribution To Individual Retirement Account Percentage Of Employees Eligible Compensation | 10.00% | 10.00% | ||