Goodwill (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Changes in the carrying value of goodwill:
Goodwill, beginning balance	$ 106,876	$ 106,876
Accumulated impairment losses, beginning balance	(79,933)	(79,933)
Goodwill balance, net, beginnging balance	26,943	26,943
Goodwill impairment recognized	0	0
Goodwill, ending balance	106,876	106,876
Accumulated impairment losses, ending balance	(79,933)	(79,933)
Goodwill balance, net, ending balance	26,943	26,943
Chemicals and Logistics [Member]
Changes in the carrying value of goodwill:
Goodwill, beginning balance	11,610	11,610
Accumulated impairment losses, beginning balance	0	0
Goodwill balance, net, beginnging balance	11,610	11,610
Goodwill impairment recognized	0	0
Goodwill, ending balance	11,610	11,610
Accumulated impairment losses, ending balance	0	0
Goodwill balance, net, ending balance	11,610	11,610
Downhole Tool [Member]
Changes in the carrying value of goodwill:
Goodwill, beginning balance	43,009	43,009
Accumulated impairment losses, beginning balance	(43,009)	(43,009)
Goodwill balance, net, beginnging balance	0	0
Goodwill impairment recognized	0	0
Goodwill, ending balance	43,009	43,009
Accumulated impairment losses, ending balance	(43,009)	(43,009)
Goodwill balance, net, ending balance	0	0
Teledrift [Member]
Changes in the carrying value of goodwill:
Goodwill, beginning balance	46,396	46,396
Accumulated impairment losses, beginning balance	(31,063)	(31,063)
Goodwill balance, net, beginnging balance	15,333	15,333
Goodwill impairment recognized	0	0
Goodwill, ending balance	46,396	46,396
Accumulated impairment losses, ending balance	(31,063)	(31,063)
Goodwill balance, net, ending balance	15,333	15,333
Artificial Lift [Member]
Changes in the carrying value of goodwill:
Goodwill, beginning balance	5,861	5,861
Accumulated impairment losses, beginning balance	(5,861)	(5,861)
Goodwill balance, net, beginnging balance	0	0
Goodwill impairment recognized	0	0
Goodwill, ending balance	5,861	5,861
Accumulated impairment losses, ending balance	(5,861)	(5,861)
Goodwill balance, net, ending balance	$ 0	$ 0