ACQUISITIONS - Furmanite (Additional Information) (Details) $ in Thousands		3 Months Ended	6 Months Ended
	Feb. 29, 2016 USD ($) shares	Jun. 30, 2016 USD ($) employee country	Jun. 30, 2016 USD ($) employee location country	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Number of employees (more than) | employee		8,300	8,300
Number of locations in which company operates | location			220
Number of countries in which the company operates | country		22	22
Goodwill		$ 361,961	$ 361,961	$ 256,654
Furmanite Corporation
Business Acquisition [Line Items]
Number of shares received for each share of common stock owned	0.215
Business acquisition, purchase price	$ 282,341
Number of common shares issued | shares	8,208,006
Acquired intangible assets	$ 70,800
Goodwill	93,903
Fair value of accounts receivable acquired	69,603
Furmanite Corporation | Selling, General and Administrative Expenses
Business Acquisition [Line Items]
Total acquisition costs		500	6,600
Separately recognized transaction, acquisition-related compensation costs		$ 0	$ 4,700
Furmanite Corporation | Customer Relationships
Business Acquisition [Line Items]
Acquired intangible assets	$ 51,600
Acquired intangible asset useful life	12 years
Furmanite Corporation | Trade Names
Business Acquisition [Line Items]
Acquired intangible assets	$ 16,900
Acquired intangible asset useful life	12 years
Furmanite Corporation | Developed Technology
Business Acquisition [Line Items]
Acquired intangible assets	$ 2,300
Acquired intangible asset useful life	10 years
Continuing Operations | Furmanite Corporation
Business Acquisition [Line Items]
Fair value of accounts receivable acquired	$ 69,600
Acquired receivables, gross contractual amount	73,800
Acquired receivables, estimated uncollectible	4,200
Discontinued Operations | Furmanite Corporation
Business Acquisition [Line Items]
Fair value of accounts receivable acquired	14,000
Acquired receivables, gross contractual amount	14,100
Acquired receivables, estimated uncollectible	$ 100