BUSINESS COMBINATION (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 17, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
BUSINESS ACQUISITIONS
Payment to acquire business, net of cash acquired					$ 465,895,000
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill		$ 194,825,000		$ 194,825,000		$ 217,609,000
Field & Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill		44,941,000		44,941,000		65,213,000
Environmental Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill		149,884,000		149,884,000		152,396,000
EQ
BUSINESS ACQUISITIONS
Percentage of outstanding shares acquired	100.00%
Payment to acquire business, net of cash acquired	$ 460,900,000
Amount of term loan which was used to funded acquisition	415,000,000
Consideration paid and the fair value of assets acquired and liabilities assumed
Current assets						112,009,000
Property and equipment						101,543,000
Identifiable intangible assets	252,874,000					252,874,000
Current liabilities						(58,312,000)
Other liabilities						(139,068,000)
Total identifiable net assets						269,046,000
Goodwill		197,600,000		197,600,000		197,600,000
Total purchase price						466,646,000
Additional information
Revenue since acquisition included in consolidated statements of operations		95,000,000		268,800,000
Operating income since acquisition included in consolidated statements of operations		11,800,000		16,100,000
Acquisition-related costs included in selling, general and administrative expenses		150,000		1,100,000
Pro forma combined:
Revenue			$ 170,894,000		458,091,000
Net income			$ 13,333,000		$ 24,835,000
Earnings per share - Basic (in dollars per share)			$ 0.62		$ 1.15
Earnings per share - Diluted (in dollars per share)			$ 0.61		$ 1.15
EQ | Field & Industrial Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill		65,200,000		65,200,000
EQ | Environmental Services
Consideration paid and the fair value of assets acquired and liabilities assumed
Goodwill		$ 132,400,000		$ 132,400,000
EQ | Permits and licenses
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	49,000,000
Previously Reported | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Current assets						111,982,000
Property and equipment						101,543,000
Identifiable intangible assets						252,874,000
Current liabilities						(57,585,000)
Other liabilities						(139,331,000)
Total identifiable net assets						269,483,000
Goodwill						197,163,000
Total purchase price						466,646,000
Adjustments | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Current assets						27,000
Current liabilities						(727,000)
Other liabilities (debit balance)						263,000
Total identifiable net assets						(437,000)
Goodwill						$ 437,000
Customer relationships | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 98,400,000
Additional information
Weighted average amortization period	15 years
Permits and licenses | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 89,600,000
Additional information
Weighted average amortization period	45 years
Tradename | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 5,481,000
Additional information
Weighted average amortization period	3 years
Customer backlog | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 4,600,000
Additional information
Weighted average amortization period	10 years
Developed software | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 3,443,000
Additional information
Weighted average amortization period	9 years
Non-compete agreements | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 900,000
Additional information
Weighted average amortization period	1 year
Internet domain and website | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 869,000
Additional information
Weighted average amortization period	19 years
Database | EQ
Consideration paid and the fair value of assets acquired and liabilities assumed
Identifiable intangible assets	$ 581,000
Additional information
Weighted average amortization period	15 years