SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND PRACTICES - Additional Information (Details)	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($) employee country Location	Jun. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) employee country segment Location customer	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2017 USD ($)	Dec. 01, 2016 USD ($)	Dec. 31, 2015 USD ($)
Accounting Policies [Abstract]
Number of operating segments | segment				3
Number of locations in which company operates (more than) | Location	220			220
Number of countries in which the company operates | country	20			20
Number of employees (more than) | employee	7,100			7,100
Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 26,681,000		$ 38,201,000	$ 26,681,000	$ 38,201,000	$ 46,216,000			$ 44,825,000
Goodwill impairment loss	$ 75,241,000	$ 0	$ 0	75,241,000	$ 0	$ 0
Discounted cash flow, forecast period						5 years
Goodwill impairment test, number of market-based approaches						2
Market capitalization in excess of carrying amount		$ 175,000,000						$ 437,000,000
Market capitalization in excess of carrying amount, percentage		33.00%						80.00%
Percentage change in stock price	43.00%
Goodwill	$ 284,680,000			284,680,000		$ 355,786,000
Accumulated impairment loss						0
Workers compensation our self-insured retention				1,000,000.0
Automobile liability self-insured retention				500,000
General liability claims we have an effective self-insured retention				3,000,000.0
Medical claims, our self-insured retention				350,000
Environmental liability claims, our self-insured retention				1,000,000
Unbilled revenues	99,943,000			$ 99,943,000		39,719,000
Sales Revenue, Net | Customer Concentration Risk
Significant Accounting Policies [Line Items]
Number of customers accounted for more than specified percentage of consolidated revenues | customer				0
Europe and Asia
Significant Accounting Policies [Line Items]
Cash and cash equivalents	9,100,000			$ 9,100,000		14,000,000
ASU 2016-09
Significant Accounting Policies [Line Items]
Cumulative-effect adjustment to opening balance of retained earnings							$ 1,000,000
TeamQualspec
Significant Accounting Policies [Line Items]
Goodwill impairment loss	21,100,000			21,140,000
Fair value in excess of consolidated net assets, percentage		65.00%
Goodwill	194,225,000			194,225,000		213,475,000
TeamFurmanite
Significant Accounting Policies [Line Items]
Goodwill impairment loss	54,100,000			54,101,000
Fair value in excess of consolidated net assets, percentage		46.00%
Goodwill	$ 56,434,000			$ 56,434,000		$ 109,059,000