INCOME TAXES (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Provision for doubtful accounts	$ 8,949	$ 10,715
Closure, post-closure and remedial liabilities	26,960	28,380
Accrued expenses	40,879
Accrued expenses	17,602	15,686
Accrued compensation	7,155	7,774
Net operating loss carryforwards	50,824	43,284
Tax credit carryforwards	16,909	16,909
Uncertain tax positions accrued interest and federal benefit	4,176	519
Stock-based compensation	2,435	3,440
Other	10,418	7,067
Total deferred tax assets	186,307	133,774
Deferred tax liabilities:
Property, plant and equipment	(184,594)	(164,246)
Operating lease right-of-use assets	(40,985)
Permits and other intangible assets	(98,654)	(103,539)
Prepaid expenses	(9,694)	(9,187)
Total deferred tax liabilities	(333,927)	(276,972)
Total net deferred tax liability before valuation allowance	(147,620)	(143,198)
Less valuation allowance	(83,643)	(79,295)
Net deferred tax liabilities	(231,263)	$ (222,493)
State and local operating loss carryforwards	201,800
Federal operating loss carryforwards	25,500
Foreign operating loss carryforwards	145,000
Foreign tax credit carryforwards	$ 16,600