Acquisitions (Allocation of Purchase Price) (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015	Nov. 23, 2015	Mar. 13, 2015	Jan. 13, 2015
Business Acquisition [Line Items]
Goodwill		$ 81,554	$ 81,752
TEW Plus LTD [Member]
Business Acquisition [Line Items]
Current assets				$ 4,420
Other assets				0
Property, plant and equipment				47
Goodwill				822
Other intangibles				1,074
Liabilities assumed				(3,597)
Total				$ 2,766
Inspection Oilfield Services (IOS) [Member]
Business Acquisition [Line Items]
Current assets					$ 19,877
Other assets					708
Property, plant and equipment					51,453
Goodwill	[1]				69,908
Other intangibles					50,354
Liabilities assumed					(23,596)
Total					$ 168,704
TEW Holdings, LTD [Member]
Business Acquisition [Line Items]
Current assets						$ 12,125
Other assets						0
Property, plant and equipment						2,398
Goodwill						8,772
Other intangibles						14,048
Liabilities assumed						(6,465)
Total						$ 30,878

[1] As a result of the impact of the downturn within the energy markets, the expectations of a prolonged period before recovery, and the reduction in active U.S. land oil rig count, the Company performed an interim test for impairment of goodwill during the third quarter of 2015 which resulted in the full impairment of goodwill related to the IOS acquisition.