PROPERTY, PLANT AND EQUIPMENT, INTANGIBLE ASSETS AND GOODWILL - Indefinite-lived Intangible Assets (Narrative) (Details)	12 Months Ended
Dec. 31, 2017
Minimum
Operating Leased Assets [Line Items]
Initial term of leases where permits are located on leased land	10 years
Maximum
Operating Leased Assets [Line Items]
Initial term of leases where permits are located on leased land	20 years

Term of the lessee's leasing arrangement renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_LesseeLeasingArrangementsOperatingLeasesRenewalTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration