SEGMENT REPORTING (Third Party Reveunes to Direct Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Total revenues	$ 936,228	$ 858,480	$ 1,668,727	$ 1,705,147
Third party revenues
Segment Reporting Information [Line Items]
Total revenues	936,228	858,480	1,668,727	1,705,147
Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Direct revenues
Segment Reporting Information [Line Items]
Total revenues	936,228	858,480	1,668,727	1,705,147
Technical Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	248,025	256,798	488,350	493,579
Technical Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	38,314	40,082	73,218	77,516
Technical Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	1,083	778	2,380	1,177
Technical Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	287,422	297,658	563,948	572,272
Industrial and Field Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	353,329	185,154	500,197	347,114
Industrial and Field Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(11,230)	(11,047)	(17,791)	(22,805)
Industrial and Field Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	(401)	36	(323)	191
Industrial and Field Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	341,698	174,143	482,083	324,500
Oil Re-refining and Recycling | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	99,104	144,016	195,911	272,937
Oil Re-refining and Recycling | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(21,428)	(54,861)	(39,685)	(102,977)
Oil Re-refining and Recycling | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	(1)	(5)	(2)	(5)
Oil Re-refining and Recycling | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	77,675	89,150	156,224	169,955
SK Environmental Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	175,876	171,324	336,560	332,712
SK Environmental Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	(8,802)	23,307	(20,384)	43,264
SK Environmental Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	3	0	3	(58)
SK Environmental Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	167,077	194,631	316,179	375,918
Lodging Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	21,171	42,872	55,275	99,566
Lodging Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	992	900	1,156	1,294
Lodging Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	80	25	97	26
Lodging Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	22,243	43,797	56,528	100,886
Oil and Gas Field Services | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	38,617	58,177	92,204	158,949
Oil and Gas Field Services | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	2,154	1,619	3,486	3,708
Oil and Gas Field Services | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	40	(22)	49	(10)
Oil and Gas Field Services | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	40,811	59,774	95,739	162,647
Corporate Items | Third party revenues
Segment Reporting Information [Line Items]
Total revenues	106	139	230	290
Corporate Items | Intersegment revenues, net
Segment Reporting Information [Line Items]
Total revenues	0	0	0	0
Corporate Items | Corporate Items, net
Segment Reporting Information [Line Items]
Total revenues	(804)	(812)	(2,204)	(1,321)
Corporate Items | Direct revenues
Segment Reporting Information [Line Items]
Total revenues	$ (698)	$ (673)	$ (1,974)	$ (1,031)