BUSINESS COMBINATIONS (2016 Acquisitions) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 465,154	$ 453,105	$ 452,669
2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	15,767
Accounts Receivables, measurement period adjustment	(1,617)
Inventories and supplies	12,515
Inventories and supplies, measurement period adjustment	(1,344)
Prepaid expenses and other current assets	777
Prepaid expenses and other current assets, measurement period adjustment	(143)
Property, plant and equipment	143,025
Property, plant and equipment, measurement period adjustment	10,320
Permits and other intangibles	28,856
Permits and other intangibles, measurement period adjustment	5,451
Current liabilities	(20,258)
Current liabilities, measurement period adjustment	(776)
Closure and post-closure liabilities, less current portion	(2,408)
Closure and post-closure liabilities, less current portion, measurement period adjustment	(699)
Remedial liabilities, less current portion	(2,041)
Remedial liabilities, less current portion, measurement period adjustment	(2,037)
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(17,019)
Deferred taxes, unrecognized tax benefits and other long-term liabilities, measurement period adjustments	(8,356)
Total identifiable net assets	159,214
Total identifiable net assets, measurement period adjustment	799
Goodwill	45,791
Goodwill, measurement period adjustment	(2,709)
Total purchase price, net of cash acquired	205,005
Total purchase price, net of cash acquired, measurement period adjustment	(1,910)
At Acquisition Dates | 2016 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	17,384
Inventories and supplies	13,859
Prepaid expenses and other current assets	920
Property, plant and equipment	132,705
Permits and other intangibles	23,405
Current liabilities	(19,482)
Closure and post-closure liabilities, less current portion	(1,709)
Remedial liabilities, less current portion	(4)
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(8,663)
Total identifiable net assets	158,415
Goodwill	48,500
Total purchase price, net of cash acquired	$ 206,915