INCOME TAXES (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Provision for doubtful accounts	$ 7,417	$ 11,189
Closure, post-closure and remedial liabilities	28,189	40,829
Accrued expenses	15,382	19,826
Accrued compensation	1,903	2,747
Net operating loss carryforwards	46,650	46,752
Tax credit carryforwards	17,504	25,348
Uncertain tax positions accrued interest and federal benefit	921	1,241
Stock-based compensation	2,268	1,993
Other	3,258	555
Total deferred tax assets	123,492	150,480
Deferred tax liabilities:
Property, plant and equipment	(144,325)	(207,799)
Permits and other intangible assets	(107,407)	(161,295)
Prepaids	(8,080)	(11,030)
Total deferred tax liabilities	(259,812)	(380,124)
Total net deferred tax liability before valuation allowance	(136,320)	(229,644)
Less valuation allowance	(68,355)	(55,189)
Total net deferred tax liability before valuation allowance	(204,675)	$ (284,833)
State and local operating loss carryforwards	186,700
Federal operating loss carryforwards	48,000
Foreign operating loss carryforwards	116,100
Foreign tax credit carryforwards	$ 17,500