Reduction in Value of Assets (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Reduction In Value Of Assets And Impairments [Line Items]
Goodwill impairment method weight, discounted cash flow method	80.00%
Goodwill impairment method weight, public company guidline method	20.00%
Reduction in value of goodwill		$ 330,500
Goodwill, Impaired, Accumulated Impairment Loss	$ 1,748,200		$ 1,748,200
Reduction in value of long-lived assets		105,859
Retirements of long-lived assets		26,102
Production Services [Member]
Reduction In Value Of Assets And Impairments [Line Items]
Reduction in value of goodwill		190,500
Impairment of Property, Plant and Equipment		12,400
Impairment of Intangible Assets (Excluding Goodwill)		21,000
Onshore Completion and Workover Services [Member]
Reduction In Value Of Assets And Impairments [Line Items]
Reduction in value of goodwill		140,000
Impairment of Property, Plant and Equipment		2,900
Impairment of Intangible Assets (Excluding Goodwill)		45,900
Drilling Products and Services [Member]
Reduction In Value Of Assets And Impairments [Line Items]
Impairment of Property, Plant and Equipment		23,700
Retirements of long-lived assets		$ 23,900