LONG-TERM DEBT - Surety Bonds, Letters of Credit and Guarantees (Narrative) (Details) $ in Millions	Dec. 31, 2016 USD ($)
Surety bonds
Guarantor Obligations [Line Items]
Outstanding surety bonds, commercial standby letters of credit and bank guarantees	$ 60.0
Commercial standby letters of credit
Guarantor Obligations [Line Items]
Outstanding surety bonds, commercial standby letters of credit and bank guarantees	103.4
Bank guarantees
Guarantor Obligations [Line Items]
Outstanding surety bonds, commercial standby letters of credit and bank guarantees	35.7
Cash secured bank guarantees
Guarantor Obligations [Line Items]
Outstanding surety bonds, commercial standby letters of credit and bank guarantees	$ 18.8