Goodwill (Changes in the Carrying Value of Goodwill) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Changes in the carrying value of goodwill:
Goodwill, beginning balance		$ 151,064	$ 146,204
Accumulated impairment losses, beginning balance		(79,933)	(79,933)
Goodwill balance, net, beginnging balance		71,131	66,271
Goodwill impairment recognized		0	0
Acquisition goodwill recognized	$ 39,300	1,689	4,860
Goodwill, ending balance		152,753	151,064
Accumulated impairment losses, ending balance		(79,933)	(79,933)
Goodwill balance, net, ending balance		72,820	71,131
Energy Chemistry Technologies [Member]
Changes in the carrying value of goodwill:
Goodwill, beginning balance		36,318	30,296
Accumulated impairment losses, beginning balance		0	0
Goodwill balance, net, beginnging balance		36,318	30,296
Goodwill impairment recognized		0	0
Acquisition goodwill recognized	18,700	0	6,022
Goodwill, ending balance		36,318	36,318
Accumulated impairment losses, ending balance		0	0
Goodwill balance, net, ending balance		36,318	36,318
Consumer and Industrial Chemistry Technologies [Member]
Changes in the carrying value of goodwill:
Goodwill, beginning balance		19,480	20,642
Accumulated impairment losses, beginning balance		0	0
Goodwill balance, net, beginnging balance		19,480	20,642
Goodwill impairment recognized		0	0
Acquisition goodwill recognized	$ 20,600	0	(1,162)
Goodwill, ending balance		19,480	19,480
Accumulated impairment losses, ending balance		0	0
Goodwill balance, net, ending balance		19,480	19,480
Downhole Tools [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
Acquisition goodwill 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
Acquisition goodwill 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
Production Technologies [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
Acquisition goodwill recognized		1,689	0
Goodwill, ending balance		7,550	5,861
Accumulated impairment losses, ending balance		(5,861)	(5,861)
Goodwill balance, net, ending balance		$ 1,689	$ 0