SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Depreciation, Depletion, Accretion and Amortization Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES [Abstract]
Depreciation	$ 250,835	$ 238,237	$ 228,866
Depletion	19,342	17,812	18,177
Accretion	11,415	11,059	11,474
Amortization of leaseholds	608	267	688
Amortization of intangible	23,765	17,565	15,618
Total	$ 305,965	$ 284,940	$ 274,823