SEGMENT REPORTING (Details 2) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Property, plant and equipment, net	$ 1,588,286	$ 1,602,170
Goodwill	565,062	570,960
Permits and other intangible, net	557,211	569,973
Total assets	3,863,955	3,953,678
Technical Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	401,130	400,544
Goodwill	45,384	45,599
Permits and other intangible, net	78,405	80,302
Total assets	701,399	699,675
Oil Re-refining and Recycling
Segment Reporting Information [Line Items]
Property, plant and equipment, net	208,977	211,513
Goodwill	170,073	171,161
Permits and other intangible, net	157,966	160,807
Total assets	631,238	643,256
SK Environmental Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	244,984	239,596
Goodwill	171,314	172,308
Permits and other intangible, net	261,894	265,104
Total assets	770,402	774,401
Industrial and Field Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	389,686	405,327
Goodwill	142,014	144,385
Permits and other intangible, net	32,751	35,332
Total assets	624,200	634,541
Oil and Gas Field Services
Segment Reporting Information [Line Items]
Property, plant and equipment, net	238,228	237,335
Goodwill	36,277	37,507
Permits and other intangible, net	26,195	28,428
Total assets	386,721	395,805
Corporate Items
Segment Reporting Information [Line Items]
Property, plant and equipment, net	105,281	107,855
Goodwill	0	0
Permits and other intangible, net	0	0
Total assets	$ 749,995	$ 806,000