Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended	0 Months Ended										1 Months Ended
	Feb. 24, 2014	Mar. 31, 2015 item	Jan. 09, 2014	Jan. 09, 2014	Aug. 15, 2013 item	Oct. 31, 2011	Nov. 24, 2014	Nov. 09, 2012	Nov. 19, 2014	May 19, 2014	Jun. 26, 2013 item	Apr. 30, 2015	Nov. 30, 2014	Dec. 31, 2014
Waterlink's Columbus, Ohio property | Accounts payable and accrued liabilities
Contingencies
Recorded liability estimates for environmental loss contingencies		0.2												$ 0.1
Waterlink's Columbus, Ohio property | Accrued pension and other liabilities
Contingencies
Recorded liability estimates for environmental loss contingencies		0.3												0.4
Big Sandy Plant
Contingencies
Civil penalty paid	1.6
Number of ground water monitoring wells to be installed		2
Big Sandy Plant | Accounts payable and accrued liabilities
Contingencies
Recorded liability estimates for environmental loss contingencies		0.1												0.1
Period of Review III
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)			0.000			0.127
Number of respondents with per-unit rates					1
Period of Review III | Maximum
Contingencies
Period of right to appeal Court affirmation of Commerce Department's remand determination							60 days
Period of Review IV
Contingencies
Ongoing duty deposit rate (as a percent)								0.00
Anti-dumping margins for cooperative, separate rate respondents (in dollars per pound)								0.47
Assessment rate finalized at deposit rate due to not participating in review (as a percent)								14.51%
Period of Review IV | Jacobi Carbons AB
Contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)								0.20
Period of Review IV | Ningxia Guanghua Cherishment Activated Carbon Co., Ltd. and affiliates
Contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)								0.96
Period of Review IV | Datong Juqiang Activated Carbon Co., Ltd.
Contingencies
Ongoing duty deposit rate (as a percent)								0.00
Period of Review VI
Contingencies
Anti-dumping margins for cooperative, separate rate respondents (in dollars per pound)									0.018	1.42
PRC-wide rate (in dollars per pound)									1.10	1.10
Number of mandatory respondents											2
Period of Review VI | Jacobi Carbons AB
Contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)									0.018	1.71
Period of Review VI | Ningxia Guanghua Cherishment Activated Carbon Co., Ltd. and affiliates
Contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)									0.018	0.93
Period of Review VI | Calgon Carbon Tianjin
Contingencies
Anti-dumping margins for cooperative, separate rate respondents (in dollars per pound)									0.018	1.42
Period Of Review VII
Contingencies
Anti-dumping margins for cooperative, separate rate respondents (in dollars per pound)												0.24
PRC-wide rate (in dollars per pound)												1.10
Period Of Review VII | Jacobi Carbons AB
Contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)												0.24
Period Of Review VII | Datong Juqiang Activated Carbon Co., Ltd.
Contingencies
Anti-dumping margins for mandatory respondents (in dollars per pound)												0.00
Period Of Review VII | Calgon Carbon Tianjin
Contingencies
Anti-dumping margins for cooperative, separate rate respondents (in dollars per pound)												0.24
Carbon Imports - Anti-dumping duties
Contingencies
Import duty (in dollars per pound)													0.018
Prior period over which Commerce Department reviews anti-dumping tariffs		12 months
Number of periods of review		7
Carbon Imports - Anti-dumping duties | Minimum
Contingencies
Period for which reviews are possible		5 years