SIGNIFICANT ACCOUNTING POLICIES (Remedial Liabilities) (Details) $ in Thousands |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2017
USD ($)
site
|
Dec. 31, 2016
USD ($)
|
Dec. 31, 2015
USD ($)
|
|
Regulatory Liabilities [Line Items] | |||
Remedial Liability | $ | $ 124,468 | $ 128,007 | $ 131,992 |
Period of time in years over which business acquisitions have been acquired | 15 years | ||
Superfund sites owned by third parties | 35 | ||
Superfund sites | 129 | ||
Minimum | |||
Regulatory Liabilities [Line Items] | |||
Remedial liabilities at acquisition, inflation rate | 1.01% | ||
Remedial liabilities at acquisition, risk-free interest rate | 1.37% | ||
Maximum | |||
Regulatory Liabilities [Line Items] | |||
Remedial liabilities at acquisition, inflation rate | 2.57% | ||
Remedial liabilities at acquisition, risk-free interest rate | 5.99% |