Commitments and Contingencies	9 Months Ended
Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is subject to legal proceedings, claims, investigations and inquiries that arise in the ordinary course of business such as, but not limited to, actions with respect to commercial, intellectual property, employment, personal injury, and environmental matters. The Company believes that it has meritorious defenses against the claims currently asserted against it and intends to defend them vigorously. While the outcome of litigation is inherently uncertain and the Company cannot be sure that it will prevail in any of the cases, subject to the matter referenced below, the Company is not aware of any matters pending that are expected to have a material adverse effect on the Company’s business, financial position, results of operations or cash flows. Lydall Gerhardi GmbH Co. & KG (“Lydall Gerhardi”), an indirect wholly-owned subsidiary of the Company and part of Lydall’s Thermal/Acoustical Metals reporting segment, has cooperated with the German Federal Cartel Office, Bundeskartellamt (“German Cartel Office”) since May 2014 in connection with an investigation related to violations of German anti-trust laws by and among certain European automotive heat shield manufacturers, including Lydall Gerhardi. In December 2016, Lydall Gerhardi agreed in principle with the German Cartel Office to pay a settlement amount of €3.3 million. The Company recorded the expense of €3.3 million (approximately $3.5 million U.S. Dollars) in December 2016. In July 2017, Lydall Gerhardi entered into a formal settlement agreement with the German Cartel Office, and remitted payment in full in August 2017 of €3.3 million (approximately $3.9 million U.S. Dollars), definitively concluding this matter. Environmental Remediation The Company has elected to remediate environmental contamination discovered prior to the closing of the Texel acquisition at a certain property in the province of Quebec, Canada (“the Property”) that was acquired by Lydall. The Company records accruals for environmental costs when such losses are probable and reasonably estimable. In 2016, the Company, through the engagement of a third-party environmental service firm, determined the final scope and timing of the remediation project and estimated the cost of the remediation project to range between $0.9 million and $1.5 million. Based upon this range of estimated remediation costs, the Company recorded an environmental liability of $0.9 million within other long-term liabilities on the Company's balance sheet at December 31, 2016. In July, 2017, the third-party environmental service firm completed its initial investigatory work and, based on information provided from the results of such work, the Company increased its environmental liability by $0.6 million at June 30, 2017. During the nine months ended September 30, 2017, the environmental liability was reduced by $0.2 million, reflecting payments made to vendors, resulting in a balance of $1.3 million at September 30, 2017. The remaining balance for the environmental liability of $1.3 million (which remains fully offset as described below) is included within other long-term liabilities on the Company's balance sheet at September 30, 2017. Pursuant to the Share Purchase Agreement, ADS has agreed to indemnify the Company from all costs and liabilities associated with the contamination and remediation work, including the costs of preparation and approval of the remediation plan and other reports in relation therewith. This indemnity was secured by an environmental escrow account, which was established in the amount of $3.0 million Canadian Dollars (approximately $2.4 million U.S. Dollars as of September 30, 2017). Should the costs and liabilities exceed the environmental escrow amount, the Company also has access to the general indemnity escrow account, which was originally established in the amount of $14.0 million Canadian Dollars (approximately $11.2 million U.S. Dollars as of September 30, 2017), and based on the Share Purchase Agreement was reduced to approximately $7.0 million Canadian Dollars (approximately $5.6 million U.S. Dollars as of September 30, 2017). Based on the foregoing, an indemnification asset of $0.9 million was also recorded in other assets at December 31, 2016 as the Company believed, and still believes collection from ADS is probable. This indemnification asset was increased by $0.6 million to reflect the most current estimate of $1.5 million at June 30, 2017. The indemnification asset was decreased by $0.2 million reflecting indemnification from ADS for payments made by the Company to its vendors during the nine months ended September 30, 2017. The resulting indemnification asset balance is $1.3 million at September 30, 2017. The accrual for remediation costs will be adjusted as further information develops, estimates change and payments to vendors are made for remediation, with an off-setting adjustment to the indemnification asset from ADS if collection is deemed probable. In the fourth quarter of 2016, as part of a groundwater discharging permitting process, water samples collected from wells and process water basins at the Company’s Rochester New Hampshire manufacturing facility, within the Performance Materials segment, showed concentrations of Perfluorinated Compounds (“PFCs”) in excess of state ambient groundwater quality standards. In January 2017, the Company received a notification from the State of New Hampshire Department of Environmental Services (“NHDES”) naming Lydall Performance Materials, Inc. a responsible party with respect to the discharge of regulated contaminants and, as such, is required to take action to investigate and remediate the impacts in accordance with standards established by the NHDES. The Company is conducting a site investigation, the scope of which has been reviewed by the NHDES, in order to assess the extent of potential soil and groundwater contamination and develop a remedial action. Based on input received from NHDES in March 2017 with regard to the scope of the site investigation, the Company recorded $0.2 million of expense in the first quarter of 2017 associated with the expected costs of conducting this site investigation. Based on additional information obtained through the results of its site investigation and correspondence with NHDES in September 2017, no additional expense was recorded in the third quarter of 2017. In the fourth quarter of 2017, the Company expects to submit its final site investigation report to the NHDES. The Company does not know the scope or extent of its future obligations, if any, that may arise from the NHDES review of the site investigation report and therefore is unable to estimate the cost of any required future corrective actions. During the nine months ended September 30, 2017, the environmental liability of $0.2 million has been reduced by $0.1 million reflecting payments made to vendors, resulting in a balance of $0.1 million at September 30, 2017. While the site investigation is nearly complete, the Company cannot assure that costs will not exceed the current estimates nor that any future corrective action at this location would not have a material effect on the Company’s financial condition, results of operations or liquidity. Provisions for such matters are charged to expense when it is probable that a liability has been incurred and reasonable estimates of the liability can be made. Estimates of environmental liabilities are based on a variety of matters, including, but not limited to, the stage of investigation, the stage of the remedial design, evaluation of existing remediation technologies, and presently enacted laws and regulations. In future periods, a number of factors could significantly impact any estimates of environmental remediation costs.

Commitments and Contingencies

The Company is subject to legal proceedings, claims, investigations and inquiries that arise in the ordinary course of business such as, but not limited to, actions with respect to commercial, intellectual property, employment, personal injury, and environmental matters. The Company believes that it has meritorious defenses against the claims currently asserted against it and intends to defend them vigorously. While the outcome of litigation is inherently uncertain and the Company cannot be sure that it will prevail in any of the cases, subject to the matter referenced below, the Company is not aware of any matters pending that are expected to have a material adverse effect on the Company’s business, financial position, results of operations or cash flows.

Lydall Gerhardi GmbH Co. & KG (“Lydall Gerhardi”), an indirect wholly-owned subsidiary of the Company and part of Lydall’s Thermal/Acoustical Metals reporting segment, has cooperated with the German Federal Cartel Office, Bundeskartellamt (“German Cartel Office”) since May 2014 in connection with an investigation related to violations of German anti-trust laws by and among certain European automotive heat shield manufacturers, including Lydall Gerhardi.

In December 2016, Lydall Gerhardi agreed in principle with the German Cartel Office to pay a settlement amount of €3.3 million. The Company recorded the expense of €3.3 million (approximately $3.5 million U.S. Dollars) in December 2016. In July 2017, Lydall Gerhardi entered into a formal settlement agreement with the German Cartel Office, and remitted payment in full in August 2017 of €3.3 million (approximately $3.9 million U.S. Dollars), definitively concluding this matter.

Environmental Remediation

The Company has elected to remediate environmental contamination discovered prior to the closing of the Texel acquisition at a certain property in the province of Quebec, Canada (“the Property”) that was acquired by Lydall. The Company records accruals for environmental costs when such losses are probable and reasonably estimable. In 2016, the Company, through the engagement of a third-party environmental service firm, determined the final scope and timing of the remediation project and estimated the cost of the remediation project to range between $0.9 million and $1.5 million. Based upon this range of estimated remediation costs, the Company recorded an environmental liability of $0.9 million within other long-term liabilities on the Company's balance sheet at December 31, 2016. In July, 2017, the third-party environmental service firm completed its initial investigatory work and, based on information provided from the results of such work, the Company increased its environmental liability by $0.6 million at June 30, 2017. During the nine months ended September 30, 2017, the environmental liability was reduced by $0.2 million, reflecting payments made to vendors, resulting in a balance of $1.3 million at September 30, 2017. The remaining balance for the environmental liability of $1.3 million (which remains fully offset as described below) is included within other long-term liabilities on the Company's balance sheet at September 30, 2017.

Pursuant to the Share Purchase Agreement, ADS has agreed to indemnify the Company from all costs and liabilities associated with the contamination and remediation work, including the costs of preparation and approval of the remediation plan and other reports in relation therewith. This indemnity was secured by an environmental escrow account, which was established in the amount of $3.0 million Canadian Dollars (approximately $2.4 million U.S. Dollars as of September 30, 2017). Should the costs and liabilities exceed the environmental escrow amount, the Company also has access to the general indemnity escrow account, which was originally established in the amount of $14.0 million Canadian Dollars (approximately $11.2 million U.S. Dollars as of September 30, 2017), and based on the Share Purchase Agreement was reduced to approximately $7.0 million Canadian Dollars (approximately $5.6 million U.S. Dollars as of September 30, 2017). Based on the foregoing, an indemnification asset of $0.9 million was also recorded in other assets at December 31, 2016 as the Company believed, and still believes collection from ADS is probable. This indemnification asset was increased by $0.6 million to reflect the most current estimate of $1.5 million at June 30, 2017. The indemnification asset was decreased by $0.2 million reflecting indemnification from ADS for payments made by the Company to its vendors during the nine months ended September 30, 2017. The resulting indemnification asset balance is $1.3 million at September 30, 2017. The accrual for remediation costs will be adjusted as further information develops, estimates change and payments to vendors are made for remediation, with an off-setting adjustment to the indemnification asset from ADS if collection is deemed probable.

In the fourth quarter of 2016, as part of a groundwater discharging permitting process, water samples collected from wells and process water basins at the Company’s Rochester New Hampshire manufacturing facility, within the Performance Materials segment, showed concentrations of Perfluorinated Compounds (“PFCs”) in excess of state ambient groundwater quality standards.

In January 2017, the Company received a notification from the State of New Hampshire Department of Environmental Services (“NHDES”) naming Lydall Performance Materials, Inc. a responsible party with respect to the discharge of regulated contaminants and, as such, is required to take action to investigate and remediate the impacts in accordance with standards established by the NHDES. The Company is conducting a site investigation, the scope of which has been reviewed by the NHDES, in order to assess the extent of potential soil and groundwater contamination and develop a remedial action. Based on input received from NHDES in March 2017 with regard to the scope of the site investigation, the Company recorded $0.2 million of expense in the first quarter of 2017 associated with the expected costs of conducting this site investigation. Based on additional information obtained through the results of its site investigation and correspondence with NHDES in September 2017, no additional expense was recorded in the third quarter of 2017. In the fourth quarter of 2017, the Company expects to submit its final site investigation report to the NHDES. The Company does not know the scope or extent of its future obligations, if any, that may arise from the NHDES review of the site investigation report and therefore is unable to estimate the cost of any required future corrective actions. During the nine months ended September 30, 2017, the environmental liability of $0.2 million has been reduced by $0.1 million reflecting payments made to vendors, resulting in a balance of $0.1 million at September 30, 2017. While the site investigation is nearly complete, the Company cannot assure that costs will not exceed the current estimates nor that any future corrective action at this location would not have a material effect on the Company’s financial condition, results of operations or liquidity. Provisions for such matters are charged to expense when it is probable that a liability has been incurred and reasonable estimates of the liability can be made. Estimates of environmental liabilities are based on a variety of matters, including, but not limited to, the stage of investigation, the stage of the remedial design, evaluation of existing remediation technologies, and presently enacted laws and regulations. In future periods, a number of factors could significantly impact any estimates of environmental remediation costs.