Reduction in Value of Assets (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015
Asset Impairment Charges [Line Items]
Retirments of Long-Lived Assets								$ 26,102	$ 42,545
Reduction in Value of Long-Lived Assets								143,803	330,194
Reduction in value of goodwill								330,500	1,326,701
Reduction in value of assets	$ 35,961	$ 1,963	$ 460,283	$ 2,198	$ 175,618	$ 755,632	$ 807,637	500,405	1,738,887
Impairment of Intangible Assets, Finite-lived								68,900
Impairment of Long-Lived Assets Held-for-use								101,000
Allowance for Notes Receivables					16,800				16,800
Restructuring Charges								39,200	46,800
Restructuring Reserve, Current	4,900				7,200			4,900	7,200
Restructuring Reserve, Noncurrent	$ 7,800				$ 11,100			7,800	11,100
Drilling Products And Services [Member]
Asset Impairment Charges [Line Items]
Retirments of Long-Lived Assets								26,100
Reduction in value of assets								48,903	40,237
Impairment of Property, Plant and Equipment								25,000	40,200
Technical Solutions [Member]
Asset Impairment Charges [Line Items]
Reduction in value of assets								25,600	124,904
Impairment of Property, Plant and Equipment								25,600	56,000
Impairment of Long-Lived Assets Held-for-use									68,900
Production Services [Member]
Asset Impairment Charges [Line Items]
Retirments of Long-Lived Assets									15,200
Reduction in value of goodwill								190,500	586,701
Reduction in value of assets								235,067	790,517
Impairment of Intangible Assets (Excluding Goodwill)								21,000	59,500
Impairment of Property, Plant and Equipment								21,400	89,700
Onshore Completion Services [Member]
Asset Impairment Charges [Line Items]
Retirments of Long-Lived Assets									27,300
Reduction in value of goodwill								140,000	740,000
Reduction in value of assets								190,835	783,229
Impairment of Intangible Assets (Excluding Goodwill)								45,900
Impairment of Property, Plant and Equipment								$ 4,900	15,900
Impairment of operating leases									$ 20,200