Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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OPERATING SEGMENTS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 segment	Mar. 31, 2014 segment	Dec. 31, 2014
OPERATING SEGMENTS
Number of reportable segments	2us-gaap_NumberOfReportableSegments	2us-gaap_NumberOfReportableSegments
OPERATING SEGMENTS
Total revenue	$ 136,651us-gaap_Revenues	$ 53,354us-gaap_Revenues
Depreciation, amortization & accretion	11,816	4,521
Capital expenditures	9,231	4,775
Total assets	877,828us-gaap_Assets	300,156us-gaap_Assets	924,257us-gaap_Assets
Treatment and disposal
OPERATING SEGMENTS
Total revenue	76,511	44,947
Services
OPERATING SEGMENTS
Total revenue	63,027	8,407
Intersegment
OPERATING SEGMENTS
Total revenue	(2,887)
Corporate
OPERATING SEGMENTS
Depreciation, amortization & accretion	135	14
Capital expenditures	542	182
Total assets	66,448	145,007
Environmental Services \| Operating Segment
OPERATING SEGMENTS
Total revenue	91,425	53,354
Depreciation, amortization & accretion	8,671	4,507
Capital expenditures	6,935	4,593
Total assets	602,647	155,149
Environmental Services \| Operating Segment \| Treatment and disposal
OPERATING SEGMENTS
Total revenue	76,511	44,947
Environmental Services \| Operating Segment \| Services
OPERATING SEGMENTS
Total revenue	17,613	8,407
Environmental Services \| Operating Segment \| Intersegment
OPERATING SEGMENTS
Total revenue	(2,699)
Field & Industrial Services \| Operating Segment
OPERATING SEGMENTS
Total revenue	45,226
Depreciation, amortization & accretion	3,010
Capital expenditures	1,754
Total assets	208,733
Field & Industrial Services \| Operating Segment \| Services
OPERATING SEGMENTS
Total revenue	45,414
Field & Industrial Services \| Operating Segment \| Intersegment
OPERATING SEGMENTS
Total revenue	$ (188)