BUSINESS COMBINATIONS (2015 Acquisitions) (Details) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2015	Apr. 11, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 453,105		$ 452,669	$ 570,960
Thermo Fluids Inc.
Business Acquisition [Line Items]
Accounts Receivable	7,585	$ 7,109
Accounts Receivables, measurement period adjustment	476
Inventories and supplies	1,791	1,791
Inventories and supplies, measurement period adjustment	0
Prepaid expenses and other current assets	665	1,749
Prepaid and other current assets, measurement period adjustment	(1,084)
Property, plant and equipment	28,862	30,468
Property, plant and equipment, measurement period adjustment	(1,606)
Permits and other intangibles	18,100	20,000
Permits and other intangibles, measurement period adjustment	(1,900)
Current liabilities	(5,845)	(5,859)
Current liabilities, measurement period adjustment	14
Closure and post-closure liabilities	(1,676)	(1,676)
Closure and post-closure liabilities, measurement period adjustment	0
Deferred taxes, unrecognized tax benefits and other long-term liabilities	(10,030)	(13,081)
Deferred taxes, unrecognized tax benefits and other long-term, measurement period adjustment	3,051
Total identifiable net assets	39,452	40,501
Total identifiable net assets, measurement period adjustment	(1,049)
Goodwill	39,134	36,591
Goodwill, measurement period adjustment	2,543
Total	78,586	$ 77,092
Total, measurement period adjustment	$ 1,494