Goodwill (Changes in the Carrying Value of Goodwill) (Details) - USD ($)	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in the carrying value of goodwill:
Goodwill, beginning balance				$ 55,798,000	$ 55,798,000	$ 55,798,000
Accumulated impairment losses, beginning balance				0	0	0
Goodwill balance, net, beginnging balance				55,798,000	55,798,000	55,798,000
Goodwill impairment recognized	$ 0	$ 0	$ 0	0	0	0	$ 0
Acquisition goodwill recognized					862,000	0
Goodwill, ending balance	56,660,000				56,660,000	55,798,000	55,798,000
Accumulated impairment losses, ending balance	0				0	0	0
Goodwill balance, net, ending balance	56,660,000				56,660,000	55,798,000	55,798,000
Energy Chemistry Technologies
Changes in the carrying value of goodwill:
Goodwill, beginning balance				36,318,000	36,318,000	36,318,000
Accumulated impairment losses, beginning balance				0	0	0
Goodwill balance, net, beginnging balance				36,318,000	36,318,000	36,318,000
Goodwill impairment recognized					0	0
Acquisition goodwill recognized					862,000	0
Goodwill, ending balance	37,180,000				37,180,000	36,318,000	36,318,000
Accumulated impairment losses, ending balance	0				0	0	0
Goodwill balance, net, ending balance	37,180,000				37,180,000	36,318,000	36,318,000
Consumer and Industrial Chemistry Technologies
Changes in the carrying value of goodwill:
Goodwill, beginning balance				19,480,000	19,480,000	19,480,000
Accumulated impairment losses, beginning balance				0	0	0
Goodwill balance, net, beginnging balance				$ 19,480,000	19,480,000	19,480,000
Goodwill impairment recognized					0	0
Acquisition goodwill recognized					0	0
Goodwill, ending balance	19,480,000				19,480,000	19,480,000	19,480,000
Accumulated impairment losses, ending balance	0				0	0	0
Goodwill balance, net, ending balance	$ 19,480,000				$ 19,480,000	$ 19,480,000	$ 19,480,000