SEGMENT REPORTING (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 ReportableSegments		Dec. 31, 2011		Dec. 31, 2010
Segment reporting information
Third party revenues									$ 2,187,908		$ 1,984,136		$ 1,731,244
Intersegment revenues, net
Segment Reporting Information Intersegment Corporate Items Net									0		0		0
Direct revenues	558,962	533,806	523,118	572,022	545,886	556,053	447,235	434,962	2,187,908		1,984,136		1,731,244
Property, plant and equipment, net	1,531,763				903,947				1,531,763		903,947
Goodwill	593,771				122,392				593,771		122,392		60,252
Permits and other intangibles, net	572,817				139,644				572,817		139,644
Total assets	3,825,806				2,085,803				3,825,806		2,085,803
Reconciliation to Consolidated Statements of Income:
Accretion of environmental liabilities									9,917		9,680		10,307
Depreciation and amortization									161,646		122,663		92,473
Income from operations	36,231	56,739	47,533	61,701	59,247	66,792	51,884	39,742	202,204		217,665		211,912
Other income	337	91	75	299	(471)	(164)	(2,868)	(2,899)	802		(6,402)		(2,795)
Loss on early extinguishment of debt									26,385		0		2,294
Interest expense, net of interest income									47,287		39,389		27,936
Income from continuing operations before provision for income taxes									127,730		184,678		184,477
Reporting segments number									4
Number of operations for which the revenues are insignificant									2
United States
Segment reporting information
Total assets	2,564,609				1,119,491				2,564,609		1,119,491
Canada
Segment reporting information
Total assets	1,260,421				961,936				1,260,421		961,936
Other foreign
Segment reporting information
Total assets	776				4,376				776		4,376
Reportable segments
Segment reporting information
Adjusted EBITDA, Total									373,767		350,008		314,692
Property, plant and equipment, net	1,531,763				903,947				1,531,763		903,947
Total Intangible assets	1,166,588				262,036				1,166,588		262,036
Total assets	3,825,806				2,085,803				3,825,806		2,085,803
Technical Services
Segment reporting information
Third party revenues									907,372		858,954		730,404
Intersegment revenues, net									28,526		24,171		30,097
Segment Reporting Information Intersegment Corporate Items Net									1,856		2,249		2,844
Direct revenues									937,754		885,374		763,345
Adjusted EBITDA, Total									244,989		235,674		190,559
Property, plant and equipment, net	320,707				308,118				320,707		308,118
Goodwill	45,404				44,410				45,404		44,410
Permits and other intangibles, net	77,773				81,605				77,773		81,605
Total Intangible assets	123,177				126,015				123,177		126,015
Total assets	610,692				604,904				610,692		604,904
Field Services
Segment reporting information
Third party revenues									256,295	[1]	280,269	[1]	448,386
Intersegment revenues, net									(17,079)	[1]	(20,144)	[1]	(32,860)
Segment Reporting Information Intersegment Corporate Items Net									752		187		(740)
Direct revenues									239,968	[1]	260,312	[1]	414,786
Adjusted EBITDA, Total									25,087		39,152		103,565
Property, plant and equipment, net	35,810				30,296				35,810		30,296
Goodwill	2,232				2,232				2,232		2,232
Permits and other intangibles, net	2,987				1,204				2,987		1,204
Total Intangible assets	5,219				3,436				5,219		3,436
Total assets	50,210				37,850				50,210		37,850
Field Services | Yellowstone River [Member]
Segment reporting information
Third party revenues											43,600
Field Services | Gulf of Mexico and Michigan [Member]
Segment reporting information
Third party revenues													253,000
Industrial Services
Segment reporting information
Third party revenues									605,235		479,376		370,569
Intersegment revenues, net									(23,338)		(9,175)		(7,929)
Segment Reporting Information Intersegment Corporate Items Net									(249)		(251)		(381)
Direct revenues									581,648		469,950		362,259
Adjusted EBITDA, Total									139,923		103,535		76,573
Property, plant and equipment, net	318,431				254,469				318,431		254,469
Goodwill	69,624				45,444				69,624		45,444
Permits and other intangibles, net	37,038				19,701				37,038		19,701
Total Intangible assets	106,662				65,145				106,662		65,145
Total assets	468,699				345,202				468,699		345,202
Oil and Gas Field Services
Segment reporting information
Third party revenues									417,530		364,486		181,872
Intersegment revenues, net									11,891		5,148		10,692
Segment Reporting Information Intersegment Corporate Items Net									(489)		(444)		130
Direct revenues									428,932		369,190		192,694
Adjusted EBITDA, Total									75,809		76,383		30,857
Property, plant and equipment, net	275,474				267,987				275,474		267,987
Goodwill	39,762				30,306				39,762		30,306
Permits and other intangibles, net	33,619				37,134				33,619		37,134
Total Intangible assets	73,381				67,440				73,381		67,440
Total assets	369,605				429,938				369,605		429,938
Safety-Kleen [Member]
Segment reporting information
Property, plant and equipment, net	514,664				0				514,664		0
Goodwill	436,749				0				436,749		0
Permits and other intangibles, net	421,400				0				421,400		0
Total Intangible assets	858,149				0				858,149		0
Total assets	1,669,361				0				1,669,361		0
Corporate Items
Segment reporting information
Third party revenues									1,476		1,051		13
Intersegment revenues, net									0		0		0
Segment Reporting Information Intersegment Corporate Items Net									(1,870)		(1,741)		(1,853)
Direct revenues									(394)		(690)		(1,840)
Adjusted EBITDA, Total									(112,041)		(104,736)		(86,862)
Property, plant and equipment, net	66,677				43,077				66,677		43,077
Total assets	$ 657,239				$ 667,909				$ 657,239		$ 667,909
Other Interest Income [Member]
Segment reporting information
Segment reporting information revenue percent									1.00%		1.00%		1.00%

[1] During the year ended December 31, 2011, third party revenues for the Field Services segment included revenues of $43.6 million associated with the oil spill response efforts in Montana. During the year ended December 31, 2010, third party revenues for the Field Services segment included revenues of $253.0 million associated with the oil spill response efforts in the Gulf of Mexico and Michigan.