BUSINESS COMBINATIONS Other (Details) (USD $)	3 Months Ended		12 Months Ended					12 Months Ended
	Dec. 31, 2012 Other 2012 Acquisitions [Member]		Dec. 31, 2012 Other 2012 Acquisitions [Member]		Dec. 31, 2011 Other 2012 Acquisitions [Member]	Oct. 02, 2012 Other 2012 Acquisitions [Member]		Dec. 31, 2012 Third Quarter 2011 Acquisitions [Member]	Sep. 30, 2012 Third Quarter 2011 Acquisitions [Member]		Dec. 31, 2012 Third Quarter 2011 Acquisitions [Member] Oil and Gas Field Services	Dec. 31, 2012 Third Quarter 2011 Acquisitions [Member] Technical Services [Member]	Dec. 31, 2012 Third Quarter 2011 Acquisitions [Member] Industrial Services
Summary of consideration paid at the acquisition date
Net debt assumed	$ 7,700,000		$ 7,700,000					$ 25,200,000
Estimated net amount due to the sellers for working capital adjustments	700,000		700,000					4,500,000
Business Acquisition, Cost of Acquired Entity, Purchase Price	107,540,000		107,540,000			107,513,000		142,100,000	142,134,000
Summary of Recognised Amounts of Identifiable Assets and Liabilities Assumed [Roll Forward]
Current assets (i)						20,215,000	[1]		41,551,000	[2]
Property, plant and equipment						51,162,000			62,969,000
Customer relationships and other intangibles						21,701,000			23,371,000
Other assets						53,000			1,671,000
Current liabilities						(5,368,000)			(23,148,000)
Asset retirement obligations									(200,000)
Other liabilities						(5,009,000)			(2,419,000)
Total identifiable net assets	83,584,000		83,584,000			82,754,000			103,795,000
Goodwill (ii)						24,759,000	[3]		38,339,000	[4]	13,300,000	11,100,000	13,900,000
Total						107,513,000			142,134,000
Current assets, Measurement Period Adjustments	55,000	[1]
Property, plant, and equipment, Measurement Period Adjustments	739,000
Customer relationships and other intangibles, , Measurement Period Adjustments	69,000
Other assets, Measurement Period Adjustments	0
Current liabilities, Measurement Period Adjustments	91,000
Other liabilities, Measurement Period Adjustments	(124,000)
Total identifiable net assets, Measurement Period Adjustments	830,000
Goodwill, Measurement Period Adjustments	(803,000)	[3]
Total, Measurement Period Adjustments	27,000
Current assets, (As adjusted)	20,270,000	[1]	20,270,000	[1]		20,215,000	[1]		41,551,000	[2]
Property, plant and equipment, (As adjusted)	51,901,000		51,901,000			51,162,000			62,969,000
Identifiable intangible assets ( As adjusted)	21,770,000		21,770,000			21,701,000			23,371,000
Other assets (As adjusted)	53,000		53,000			53,000			1,671,000
Current liabilities (As adjusted)	(5,277,000)		(5,277,000)			(5,368,000)			(23,148,000)
Asset retirement obligations (As adjusted)									(200,000)
Other liabilities (As adjusted)	(5,133,000)		(5,133,000)			(5,009,000)			(2,419,000)
Goodwill (As adjusted)	23,956,000	[3]	23,956,000	[3]		24,759,000	[3]		38,339,000	[4]	13,300,000	11,100,000	13,900,000
Total (As adjusted)	107,540,000		107,540,000			107,513,000		142,100,000	142,134,000
Business Combination, Acquired Receivables, Fair Value	12,700,000		12,700,000						21,400,000
Customer receivables, gross amount due	13,300,000		13,300,000						22,100,000
Acquisition related costs			400,000					800,000
Business Acquisition, Pro Forma Revenue			2,268,621,000		2,112,297,000
Pro forma combined net income			$ 130,322,000		$ 126,768,000

[1] The preliminary fair value of the financial assets acquired included customer receivables with an aggregate fair value of $12.7 million. Combined gross amounts due were $13.3 million.

[2] The fair value of the financial assets acquired included customer receivables with an aggregate fair value of $21.4 million. Combined gross amounts due were $22.1 million.

[3] Goodwill represents the excess of the fair value of the net assets acquired over the purchase price attributed to expected operating and cross selling synergies. The goodwill has been assigned to the Industrial Services segment and will not be deductible for tax purposes.

[4] Goodwill represents the excess of the fair value of the net assets acquired over the purchase price. Goodwill of $13.3 million, $11.1 million and $13.9 million has been assigned to the Oil and Gas Field Services segment, the Technical Services segment, and the Industrial Services segment, respectively and will not be deductible for tax purposes.