Acquisitions (Allocation of Purchase Price) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	Nov. 23, 2015	Mar. 13, 2015	Jan. 13, 2015	Dec. 31, 2014	Dec. 30, 2014	Oct. 29, 2014	Jul. 07, 2014
Business Acquisition [Line Items]
Goodwill		$ 18,932	$ 81,752				$ 82,949
TEW Plus LTD [Member]
Business Acquisition [Line Items]
Current assets				$ 4,420
Other assets				0
Property, plant and equipment				47
Goodwill	[1]			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	[1]				51,453
Goodwill	[1]				69,908
Other intangibles	[1],[2]				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	[1]					8,772
Other intangibles						14,048
Liabilities assumed						(6,465)
Total						$ 30,878
Chemtec Energy Services, LLC [Member]
Business Acquisition [Line Items]
Current assets								$ 15,528
Other assets								0
Property, plant and equipment								4,705
Goodwill	[1]							22,302
Other intangibles								33,130
Liabilities assumed								(6,756)
Total								$ 68,909
FWO [Member]
Business Acquisition [Line Items]
Current assets									$ 131
Other assets									0
Property, plant and equipment									0
Goodwill	[1]								971
Other intangibles									419
Liabilities assumed									(418)
Total									$ 1,103
Carr Concrete [Member]
Business Acquisition [Line Items]
Current assets										$ 3,180
Other assets										45
Property, plant and equipment										7,648
Goodwill	[1]									1,936
Other intangibles										1,348
Liabilities assumed										(1,677)
Total										$ 12,480

[1] See Note 4 Goodwill and Other Intangible Assets, and Note 7 Property, Plant, and Equipment, with respect to an impairment of property, plant, and equipment, intangible assets, and goodwill related to this acquisition.

[2] See Note 4 Goodwill and Other Intangible Assets, with respect to an impairment of intangible assets related to this acquisition.