Goodwill and Other Identifiable Intangible Assets - Changes in Carrying Amount of Goodwill by Segment (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)
Goodwill
Number of reporting units | item	6
Changes in the carrying amount of goodwill
Balance as of beginning of year	$ 26,197	$ 26,552
Foreign currency translation	(420)	(355)
Balance as of end of period	$ 25,777	26,197
Activated Carbon and Service
Goodwill
Number of reporting units | item	2
Changes in the carrying amount of goodwill
Balance as of beginning of year	$ 19,753	19,961
Foreign currency translation	(149)	(208)
Balance as of end of period	19,604	19,753
Equipment
Changes in the carrying amount of goodwill
Balance as of beginning of year	6,384	6,531
Foreign currency translation	(271)	(147)
Balance as of end of period	6,113	6,384
Consumer
Changes in the carrying amount of goodwill
Balance as of beginning of year	60	60
Balance as of end of period	$ 60	$ 60