OPERATING SEGMENTS - Summarized Financial Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) segment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
OPERATING SEGMENTS
Number of reportable segments | segment			2
Total revenue	$ 124,824	$ 148,414	$ 360,493	$ 424,797
Depreciation, amortization and accretion	10,136	10,675	29,549	34,492
Capital expenditures	2,956	6,317	22,550	25,693
Total assets	773,310	863,376	773,310	863,376	$ 771,987
Treatment and Disposal Revenue
OPERATING SEGMENTS
Total revenue	74,456	76,991	213,738	226,768
Transportation and Logistics
OPERATING SEGMENTS
Total revenue	21,139	24,300	62,170	69,765
Industrial Cleaning
OPERATING SEGMENTS
Total revenue	5,025	28,059	16,497	71,601
Technical Services
OPERATING SEGMENTS
Total revenue	20,364	17,640	57,136	50,243
Remediation
OPERATING SEGMENTS
Total revenue	3,326	1,253	8,816	5,492
Other
OPERATING SEGMENTS
Total revenue	514	171	2,136	928
Corporate
OPERATING SEGMENTS
Depreciation, amortization and accretion	115	126	362	405
Capital expenditures	546	436	2,358	1,879
Total assets	59,118	62,614	59,118	62,614
Environmental Services | Operating Segment
OPERATING SEGMENTS
Total revenue	87,785	91,947	252,106	266,314
Depreciation, amortization and accretion	8,665	8,619	25,117	26,047
Capital expenditures	1,960	4,365	18,309	17,226
Total assets	589,841	594,421	589,841	594,421
Environmental Services | Operating Segment | Treatment and Disposal Revenue
OPERATING SEGMENTS
Total revenue	70,719	73,487	204,352	217,045
Environmental Services | Operating Segment | Transportation and Logistics
OPERATING SEGMENTS
Total revenue	17,066	18,460	47,754	49,269
Field & Industrial Services | Operating Segment
OPERATING SEGMENTS
Total revenue	37,039	56,467	108,387	158,483
Depreciation, amortization and accretion	1,356	1,930	4,070	8,040
Capital expenditures	450	1,516	1,883	6,588
Total assets	124,351	206,341	124,351	206,341
Field & Industrial Services | Operating Segment | Treatment and Disposal Revenue
OPERATING SEGMENTS
Total revenue	3,737	3,504	9,386	9,723
Field & Industrial Services | Operating Segment | Transportation and Logistics
OPERATING SEGMENTS
Total revenue	4,073	5,840	14,416	20,496
Field & Industrial Services | Operating Segment | Industrial Cleaning
OPERATING SEGMENTS
Total revenue	5,025	28,059	16,497	71,601
Field & Industrial Services | Operating Segment | Technical Services
OPERATING SEGMENTS
Total revenue	20,364	17,640	57,136	50,243
Field & Industrial Services | Operating Segment | Remediation
OPERATING SEGMENTS
Total revenue	3,326	1,253	8,816	5,492
Field & Industrial Services | Operating Segment | Other
OPERATING SEGMENTS
Total revenue	$ 514	$ 171	$ 2,136	$ 928