Acquisitions (Identifiable Intangible Assets Acquired) (Details) - USD ($) $ in Thousands	Nov. 23, 2015	Mar. 13, 2015	Jan. 13, 2015
TEW Plus LTD
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets	$ 1,074
TEW Plus LTD | Trade name
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets	0
TEW Plus LTD | Customer relationships
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets	817
TEW Plus LTD | Technology
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets	203
TEW Plus LTD | Non-competition agreements
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets	$ 54
Inspection Oilfield Services (IOS)
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets		$ 50,354
Inspection Oilfield Services (IOS) | Trade name
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets		2,641
Inspection Oilfield Services (IOS) | Customer relationships
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets		41,171
Inspection Oilfield Services (IOS) | Technology
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets		4,364
Inspection Oilfield Services (IOS) | Non-competition agreements
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets		$ 2,178
TEW Holdings, LTD
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets			$ 14,048
TEW Holdings, LTD | Trade name
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets			870
TEW Holdings, LTD | Customer relationships
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets			10,035
TEW Holdings, LTD | Technology
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets			2,480
TEW Holdings, LTD | Non-competition agreements
Acquired Finite-Lived Intangible Assets
Fair value estimate of acquired identifiable intangible assets			$ 663