SEGMENT REPORTING (Segment Information, Revenues, EBITA, and Reconciliation to the Consolidated Statement of Operations) (Details) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2016 USD ($) operation segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Reporting segments number | segment										6
Number of operations for which the revenues are insignificant | operation										2
Total revenues	$ 692,113	$ 729,520	$ 697,510	$ 636,083	$ 713,044	$ 893,366	$ 936,228	$ 732,499		$ 2,755,226	$ 3,275,137	$ 3,401,636
Adjusted EBITDA										400,354	504,167	521,919
Reconciliation to Consolidated Statements of Operations:
Accretion of environmental liabilities										10,177	10,402	10,612
Depreciation and amortization										287,002	274,194	276,083
Goodwill impairment charges		34,000					32,000			34,013	31,992	123,414
Income (loss) from operations	21,943	16,802	34,504	(4,087)	25,549	93,970	60,758	7,302		69,162	187,579	111,810
Other (income) expense, net	$ (6,932)	198	$ 189	$ 350	$ 990	$ 139	$ 660	$ (409)		(6,195)	1,380	(4,380)
Gain on sale of business		$ (16,400)								(16,884)	0	0
Interest expense, net of interest income										83,525	76,553	77,668
(Loss) income before (benefit) provision for income taxes										8,716	109,646	38,522
Technical Services
Segment Reporting Information [Line Items]
Total revenues										906,495	991,410	1,043,267
Adjusted EBITDA										271,176	291,737	328,130
Reconciliation to Consolidated Statements of Operations:
Goodwill impairment charges										0	0
Industrial and Field Services
Segment Reporting Information [Line Items]
Total revenues										618,245	1,023,638	795,249
Adjusted EBITDA										51,191	161,447	98,266
Reconciliation to Consolidated Statements of Operations:
Goodwill impairment charges										0	0
Safety-Kleen
Segment Reporting Information [Line Items]
Total revenues										1,110,727	1,060,926	1,200,907
Adjusted EBITDA										219,546	172,262	165,547
Reconciliation to Consolidated Statements of Operations:
Goodwill impairment charges									$ 123,400	0	0
Oil, Gas and Lodging Services
Segment Reporting Information [Line Items]
Total revenues										116,692	198,705	361,937
Adjusted EBITDA										(3,292)	11,704	90,877
Reconciliation to Consolidated Statements of Operations:
Goodwill impairment charges										34,013	31,992
Corporate Items
Segment Reporting Information [Line Items]
Total revenues										3,067	458	276
Adjusted EBITDA										(138,267)	(132,983)	(160,901)
Intersegment revenues, net | Technical Services
Segment Reporting Information [Line Items]
Total revenues										147,866	144,084	156,543
Intersegment revenues, net | Industrial and Field Services
Segment Reporting Information [Line Items]
Total revenues										(35,724)	(32,903)	(46,424)
Intersegment revenues, net | Safety-Kleen
Segment Reporting Information [Line Items]
Total revenues										(115,013)	(119,232)	(121,382)
Intersegment revenues, net | Oil, Gas and Lodging Services
Segment Reporting Information [Line Items]
Total revenues										2,871	8,051	11,263
Intersegment revenues, net | Corporate Items
Segment Reporting Information [Line Items]
Total revenues										0	0	0
Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues										0	0	0
Corporate Items, net | Technical Services
Segment Reporting Information [Line Items]
Total revenues										2,374	3,586	5,573
Corporate Items, net | Industrial and Field Services
Segment Reporting Information [Line Items]
Total revenues										(306)	(782)	271
Corporate Items, net | Safety-Kleen
Segment Reporting Information [Line Items]
Total revenues										369	(5)	(63)
Corporate Items, net | Oil, Gas and Lodging Services
Segment Reporting Information [Line Items]
Total revenues										320	383	75
Corporate Items, net | Corporate Items
Segment Reporting Information [Line Items]
Total revenues										(2,757)	(3,182)	(5,856)
Direct revenues
Segment Reporting Information [Line Items]
Total revenues										2,755,226	3,275,137	3,401,636
Direct revenues | Technical Services
Segment Reporting Information [Line Items]
Total revenues										1,056,735	1,139,080	1,205,383
Direct revenues | Industrial and Field Services
Segment Reporting Information [Line Items]
Total revenues										582,215	989,953	749,096
Direct revenues | Safety-Kleen
Segment Reporting Information [Line Items]
Total revenues										996,083	941,689	1,079,462
Direct revenues | Oil, Gas and Lodging Services
Segment Reporting Information [Line Items]
Total revenues										119,883	207,139	373,275
Direct revenues | Corporate Items
Segment Reporting Information [Line Items]
Total revenues										$ 310	$ (2,724)	$ (5,580)