Commitments and Contingencies - Environmental and Anti-Dumping (Details) $ in Millions	1 Months Ended									3 Months Ended	9 Months Ended
	Nov. 30, 2017 $ / lb	Oct. 31, 2017 USD ($)	Apr. 30, 2017 company	Sep. 30, 2016 $ / lb	Oct. 31, 2015 $ / lb	Nov. 30, 2014 $ / lb	Jan. 31, 2014 $ / lb	Feb. 28, 2013	Oct. 31, 2011 USD ($) $ / lb	Jun. 30, 2017 objector	Sep. 30, 2017 USD ($) item $ / lb	Dec. 31, 2016 USD ($)
Waterlink's Columbus, Ohio property | Accrued pension and other liabilities
Commitments and contingencies
Recorded liability for environmental loss contingencies | $											$ 0.3	$ 0.3
Big Sandy Plant
Commitments and contingencies
Number of ground water monitoring wells installed | item											2
Recorded liability for environmental loss contingencies | $											$ 0.0	$ 0.0
Period of Review III
Commitments and contingencies
Ongoing duty deposit rate (as a percent)							0.000		0.000
Receivable recorded for anticipated refunds of anti-dumping duties | $									$ 1.1
Tariff collection rate for cooperative respondents (in dollars per pound)						0	0		0.127
Number of parties that appealed court judgement | objector										0
Duty deposits received | $		$ 0.7
Period of Review VII
Commitments and contingencies
Anti-dumping margins for separate rate respondents (in dollars per pound)					0.476
Period of Review VII | Calgon Carbon Tianjin
Commitments and contingencies
Anti-dumping margins for separate rate respondents (in dollars per pound)					0.476
Period of Review VII | Minimum
Commitments and contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)					0.00
Period of Review VII | Maximum
Commitments and contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)					0.476
Period of Review VIII
Commitments and contingencies
Anti-dumping margins for separate rate respondents (in dollars per pound)				0.616
Period of Review VIII | Calgon Carbon Tianjin
Commitments and contingencies
Anti-dumping margins for separate rate respondents (in dollars per pound)				0.616
Period of Review VIII | Minimum
Commitments and contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)				0.009
Period of Review VIII | Maximum
Commitments and contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)				0.797
Period Of Review IX | Minimum
Commitments and contingencies
Import (anti-dumping) duty (in dollars per pound)	0.00
Period Of Review IX | Maximum
Commitments and contingencies
Import (anti-dumping) duty (in dollars per pound)	0.10
Period Of Review X
Commitments and contingencies
Number of mandatory respondents | company			2
Carbon Imports - Anti-dumping duties
Commitments and contingencies
Import (anti-dumping) duty (in dollars per pound)											0.616
Prior period over which Commerce Department reviews anti-dumping tariffs											12 months
Carbon Imports - Anti-dumping duties | Minimum
Commitments and contingencies
Period for which reviews are possible								5 years