Rationalizations and Impairments (Rationalization-Roll-forward) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
2013 Rationalization Initiatives
Restructuring Reserve [Roll Forward]
Beginning balance	$ 1,035	$ 18,421
Charges incurred	193	613
Change in estimates	(214)	(153)
Payments and settlements	(1,057)	(16,494)
Effect of change in currency exchange rates	(212)	(1,658)
Ending balance	173	1,035
2014 Engineered Solutions Rationalization
Restructuring Reserve [Roll Forward]
Beginning balance	1,655	0
Charges incurred	50	2,611
Change in estimates	(716)	(40)
Payments and settlements	(979)	(916)
Ending balance	10	1,655
2014 Corporate and Research & Development Rationalization
Restructuring Reserve [Roll Forward]
Beginning balance	6,873	0
Charges incurred	(33)	8,159
Change in estimates	67	(21)
Payments and settlements	(5,046)	(1,155)
Effect of change in currency exchange rates	(121)	(152)
Ending balance	1,606	6,873
2015 Advanced Graphite Materials Rationalization
Restructuring Reserve [Roll Forward]
Beginning balance	0
Charges incurred	5,543
Payments and settlements	(2,032)
Effect of change in currency exchange rates	(38)
Ending balance	$ 3,473	$ 0