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ASSET RETIREMENT OBLIGATION (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Regulatory Assets [Line Items]    
Related asset removal period 55 years  
Asset Retirement Obligation, Roll Forward Analysis    
Long-term portion of asset retirement obligation $ 47,093 $ 42,067
Asset Retirement Obligation Costs    
Asset Retirement Obligation, Roll Forward Analysis    
Beginning balance 42,491 48,056
Adjustment due to changes in estimates 2,317 (5,343)
Accretion of liability 3,555 5,090
Liabilities settled (2,880) (4,310)
Foreign Currency 2,501 (1,002)
Ending balance 47,984 42,491
Less: current portion 891 424
Long-term portion of asset retirement obligation $ 47,093 $ 42,067