VALUATION AND QUALIFYING ACCOUNTS - Activity (Details) - USD ($) $ in Millions |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Allowance for Doubtful Accounts [Member] | |||
Movement in Valuation Allowances and Reserves [Roll Forward] | |||
Beginning Balance | $ 17.7 | $ 16.5 | $ 14.3 |
Provision for Doubtful Accounts | 25.1 | 19.5 | 14.1 |
Write-Offs | (21.9) | (18.3) | (11.9) |
Ending Balance | 20.9 | 17.7 | 16.5 |
Estimated Revenue Adjustments [Member] | |||
Movement in Valuation Allowances and Reserves [Roll Forward] | |||
Beginning Balance | 4.1 | 4.0 | 3.1 |
Provision for Estimated Revenue Adjustments | 14.4 | 7.9 | 6.1 |
Write-Offs | (12.3) | (7.8) | (5.2) |
Ending Balance | $ 6.2 | $ 4.1 | $ 4.0 |