BUSINESS COMBINATIONS (Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 469,860	$ 465,154
2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	16,396
Measurement period adjustments, accounts receivable	629
Inventories and supplies	12,688
Measurement period adjustment, inventories and supplies	173
Prepaid and other current assets	752
Measurement period adjustment, prepaid and other current assets	(25)
Property, plant and equipment	143,650
Measurement period adjustments, property, plant and equipment	625
Permits and other intangibles	28,856
Measurement period adjustments, permits and other intangibles	0
Current liabilities	(19,866)
Measurement period adjustments, current liabilities	392
Closure and post-closure liabilities	(3,004)
Measurement period adjustments, closure and post-closure liabilities	(596)
Remedial liabilities, less current portion	(2,025)
Measurement period adjustments, remedial liabilities, less current portion	16
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(17,475)
Measurement period adjustments, deferred taxes, unrecognized tax benefits and other long-term liabilities	(456)
Total identifiable net assets	159,972
Measurement period adjustments, total identifiable net assets	758
Goodwill	45,060
Measurement period adjustments, goodwill	(731)
Total purchase price, net of cash acquired	205,032
Measurement period adjustments, total purchase price, net of cash acquired	$ 27
At Acquisition Dates As Reported December 31, 2016 | 2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable		15,767
Inventories and supplies		12,515
Prepaid and other current assets		777
Property, plant and equipment		143,025
Permits and other intangibles		28,856
Current liabilities		(20,258)
Closure and post-closure liabilities		(2,408)
Remedial liabilities, less current portion		(2,041)
Deferred taxes, unrecognized tax benefits and other long-term liabilities		(17,019)
Total identifiable net assets		159,214
Goodwill		45,791
Total purchase price, net of cash acquired		$ 205,005