Acquisitions (Allocation of Purchase Price) (Details) - USD ($) $ in Thousands		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		$ 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			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
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								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									1,936
Other intangibles									1,348
Liabilities assumed									(1,677)
Total									$ 12,480

[1] See Note 4 with respect to an impairment of the goodwill related to this acquisition.