ACQUISITIONS - Summary of Purchase Price Allocation (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Feb. 29, 2016	Dec. 31, 2015	Jul. 07, 2015
Business Acquisition [Line Items]
Current assets of discontinued operations	$ 14,810		$ 0
Goodwill	361,961		256,654
Current liabilities of discontinued operations	$ 2,328		$ 0
Furmanite Corporation
Business Acquisition [Line Items]
Cash and cash equivalents		$ 37,734
Accounts receivable		69,603
Inventory		27,800
Current deferred tax assets		11,563
Prepaid expenses and other current assets		24,026
Current assets of discontinued operations		14,760
Plant, property and equipment		70,526
Intangible assets		70,800
Goodwill		93,903
Other non-current assets		3,709
Total assets acquired		424,424
Accounts payable		12,360
Other accrued liabilities		26,894
Income taxes payable		229
Current liabilities of discontinued operations		1,434
Non-current deferred tax liabilities		84,963
Defined benefit pension liability		13,509
Other long-term liabilities		2,694
Total liabilities assumed		142,083
Net assets acquired		$ 282,341
Qualspec Group
Business Acquisition [Line Items]
Cash and cash equivalents				$ 3,981
Accounts receivable				21,495
Current deferred tax assets				279
Prepaid expenses and other current assets				1,049
Plant, property and equipment				15,472
Intangible assets				78,100
Goodwill				148,482
Other non-current assets				138
Total assets acquired				268,996
Accounts payable				2,892
Other accrued liabilities				7,581
Non-current deferred tax liabilities				2,982
Total liabilities assumed				13,455
Net assets acquired				$ 255,541