Commitments and Contingencies	12 Months Ended
Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies We are involved in various legal proceedings that have arisen in the normal course of operations, including the proceedings summarized below. The effect of the outcome of these matters on our financial statements cannot be predicted with certainty as any such effect depends on the amount and timing of the resolution of such matters. Other than the litigation described below, we do not believe that any of our outstanding litigation would have a material adverse effect on our business or prospects. Environmental. We are subject to a wide variety of laws and regulations concerning the protection of the environment, both with respect to the operations at many of our properties and with respect to remediating environmental conditions that may exist at our own or other properties. We accrue for environmental expenses resulting from existing conditions that relate to past operations when the costs are probable and reasonably estimable. In the acquisition agreement pursuant to which a predecessor to Tyco sold our businesses to a previous owner in August 1999, Tyco agreed to indemnify us and our affiliates, among other things, for all “Excluded Liabilities.” Excluded Liabilities include, among other things, substantially all liabilities relating to the time prior to August 1999, including environmental liabilities. The indemnity survives indefinitely. Tyco’s indemnity does not cover liabilities to the extent caused by us or the operation of our businesses after August 1999, nor does it cover liabilities arising with respect to businesses or sites acquired after August 1999. Since 2007, Tyco has engaged in multiple corporate restructurings, split-offs and divestitures. While none of these transactions directly affects the indemnification obligations of the Tyco indemnitors under the 1999 acquisition agreement, the result of such transactions is that the assets of, and control over, such Tyco indemnitors has changed. Should any of these Tyco indemnitors become financially unable or fail to comply with the terms of the indemnity, we may be responsible for such obligations or liabilities. In September 1987, we implemented an Administrative Consent Order (“ACO”) for our Burlington, New Jersey property, which was required under the New Jersey Environmental Cleanup Responsibility Act (now known as the Industrial Site Recovery Act). The ACO required soil and ground-water cleanup, and we completed, and received final approval on, the soil cleanup required by the ACO. We retained this property related to the sale of our former U.S. Pipe segment. We expect ground-water issues as well as issues associated with the demolition of former manufacturing facilities at this site will continue and remediation by us could be required. Long-term ground-water monitoring may also be required, but we do not know how long such monitoring would be required and do not believe monitoring or further remediation costs, if any, will have a material adverse effect on any of our financial statements. On July 13, 2010, Rohcan Investments Limited, the former owner of property leased by Mueller Canada Ltd. and located in Milton, Ontario, filed suit against Mueller Canada Ltd. and its directors seeking C$10.0 million in damages arising from the defendants’ alleged environmental contamination of the property and breach of lease. Mueller Canada Ltd. leased the property from 1988 through 2008. We are pursuing indemnification from a former owner for certain potential liabilities that are alleged in this lawsuit, and we have accrued for other liabilities not covered by indemnification. On December 7, 2011, the Court denied the plaintiff’s motion for summary judgment. The purchaser of U.S. Pipe has been identified as a “potentially responsible party” (“PRP”) under the Comprehensive Environmental Response, Compensation and Liability Act (“Superfund”) in connection with a former manufacturing facility operated by U.S. Pipe that was in the vicinity of a Superfund site located in North Birmingham, Alabama. Under the terms of the acquisition agreement relating to the sale of U.S. Pipe, we agreed to indemnify the purchaser for certain environmental liabilities, including those arising out of the former manufacturing site in North Birmingham. Accordingly, the purchaser tendered the matter to us for indemnification, which we accepted. Ultimate liability for the site will depend on many factors that have not yet been determined, including the determination of EPA’s remediation costs, the number and financial viability of the other PRPs (there are four other PRPs currently) and the determination of the final allocation of the costs among the PRPs, if any. Accordingly, because the amount of such costs cannot be reasonably estimated at this time, no amounts had been accrued for this matter at September 30, 2015. Walter Energy. Each member of the Walter Energy consolidated group, which included us through December 14, 2006, is jointly and severally liable for the federal income tax liability of each other member of the consolidated group for any year in which it is a member of the group at any time during such year. Accordingly, we could be liable in the event any such federal income tax liability is incurred, and not discharged, by any other member of the Walter Energy consolidated group for any period during which we were included in the Walter Energy consolidated group. Walter Energy effectively controlled all of our tax decisions for periods during which we were a member of the Walter Energy consolidated group for federal income tax purposes and certain combined, consolidated or unitary state and local income tax groups. Under the terms of an income tax allocation agreement between us and Walter Energy, dated May 26, 2006, we generally compute our tax liability on a stand-alone basis, but Walter Energy has sole authority to respond to and conduct all tax proceedings (including tax audits) relating to our federal income and combined state tax returns, to file all such tax returns on our behalf and to determine the amount of our liability to (or entitlement to payment from) Walter Energy for such previous periods. A dispute exists with the IRS regarding federal income taxes allegedly owed by the Walter Energy consolidated group from multiple tax years. According to Walter Energy's quarterly report on Form 10-Q filed with the SEC on November 5, 2015 (the "Walter Form 10-Q"), at September 30, 2015, Walter Energy had $33.0 million of accruals for unrecognized tax benefits on the matters subject to disposition. Walter Energy has stated it believes that all of its current and prior tax filing positions have substantial merit and intends to vigorously defend any tax claims asserted. In addition, Walter Energy stated in the Walter Form 10-Q that it believes that it has sufficient accruals to address any claims, including interest and penalties, and does not believe that any potential difference between the final settlements and the amounts accrued will have a material effect on its financial position, but such potential difference could be material to results of its operations in a future reporting period. Walter Energy filed a petition for reorganization under Chapter 11 of the U.S. Bankruptcy Code in July 2015. We are currently monitoring the filing inasmuch as we could be liable for all or a portion of this federal income tax liability if it is incurred, and not discharged, for any period during which we were included in the Walter Energy consolidated group. In accordance with the income tax allocation agreement, Walter Energy used certain tax assets of one of our predecessors in its calendar 2006 tax return for which payment to us is required. The income tax allocation agreement only requires Walter Energy to make the payment upon realization of this tax benefit by receiving a refund or otherwise offsetting taxes due. Walter Energy currently owes us $11.6 million that is payable pending completion of an IRS audit of Walter Energy’s 2006 tax year and the related refund of tax from that year. As a result of the aforementioned Chapter 11 petition, we recorded a provision for doubtful accounts of $11.6 million in the quarter ended June 30, 2015. During the quarter ended September 30, 2015, we wrote off this receivable. Indemnifications. We are a party to contracts in which it is common for us to agree to indemnify third parties for certain liabilities that arise out of or relate to the subject matter of the contract. In some cases, this indemnity extends to related liabilities arising from the negligence of the indemnified parties, but usually excludes any liabilities caused by gross negligence or willful misconduct. We cannot estimate the potential amount of future payments under these indemnities until events arise that would trigger a liability under the indemnities. Additionally, in connection with the sale of assets and the divestiture of businesses, such as the divestiture of our U.S. Pipe segment, we may agree to indemnify buyers and related parties for certain losses or liabilities incurred by these parties with respect to: (i) the representations and warranties made by us to these parties in connection with the sale and (ii) liabilities related to the pre-closing operations of the assets or business sold. Indemnities related to pre-closing operations generally include certain environmental and tax liabilities and other liabilities not assumed by these parties in the transaction. Indemnities related to the pre-closing operations of sold assets or businesses normally do not represent additional liabilities to us, but simply serve to protect these parties from potential liability associated with our obligations existing at the time of the sale. As with any liability, we have accrued for those pre-closing obligations that are considered probable and reasonably estimable. Should circumstances change, increasing the likelihood of payments related to a specific indemnity, we will accrue a liability when future payment is probable and the amount is reasonably estimable. Other Matters. Anvil is in a dispute with Victaulic Company (“Victaulic”) regarding two patents held by Victaulic, U.S. Patent 7,086,131 (the “131 Patent”) and U.S. Patent 7,712,796 (the “796 Patent” and collectively with the 131 Patent, the “U.S. Patents”), which Anvil believes are invalid. The U.S. Patents potentially relate to a coupling product currently manufactured and marketed by Anvil. Anvil filed multiple reexamination requests with the U.S. Patent and Trademark Office (the “PTO”) regarding the U.S. Patents, and the PTO granted the requests. Although the PTO examiner initially invalidated most of the claims of the 796 Patent, the PTO examiner affirmed the validity of the 796 Patent in September 2014. In April 2015, the PTO examiner invalidated the original claim of the 131 Patent but found several claims added during reexamination that appear substantially similar to those included in the 796 Patent patentable. The PTO examiners’ decisions with respect to the U.S. Patents have been appealed by Anvil and Victaulic. Relatedly, Anvil and Victaulic are engaged in lawsuits in the U.S. District Court for the Northern District of Georgia and in the Federal Court of Toronto, Ontario, Canada. The Georgia District Court litigation has been stayed pending the final outcome of the ongoing reexaminations of the U.S. Patents by the PTO. Although Anvil intends to continue to vigorously contest the validity of the U.S. Patents, as well as Victaulic’s related patents in Canada, and to defend itself against any counterclaims made by Victaulic, the probability of a favorable or unfavorable outcome with respect to these proceedings is unknown. Any number of potential outcomes is possible due to the multiple claims associated with the proceedings, each of which is in different stages and subject to appeal. Further, there are a number of highly complex factual and technical issues involved, and it is uncertain whether a favorable or unfavorable result with respect to a particular ruling or proceeding will impact the other matters in controversy. Accordingly, we have not recorded any accrual with respect to these proceedings and a range of liability is not reasonably estimable. We are party to a number of other lawsuits arising in the ordinary course of business, including product liability cases for products manufactured by us or third parties. We provide for costs relating to these matters when a loss is probable and the amount is reasonably estimable. Administrative costs related to these matters are expensed as incurred. The effect of the outcome of these matters on our future financial statements cannot be predicted with certainty as any such effect depends on the amount and timing of the resolution of such matters. While the results of litigation cannot be predicted with certainty, we believe that the final outcome of such other litigation is not likely to have a materially adverse effect on our business or prospects. Operating Leases. We maintain operating leases primarily for equipment and facilities. Rent expense was $10.4 million, $9.3 million and $8.4 million for 2015, 2014 and 2013, respectively. Future minimum payments under non-cancellable operating leases are $6.7 million, $5.5 million, $3.0 million, $1.7 million and $0.6 million during 2016, 2017, 2018, 2019 and 2020, respectively. Total minimum payments due beyond 2020 are $1.9 million.

Commitments and Contingencies

We are involved in various legal proceedings that have arisen in the normal course of operations, including the proceedings summarized below. The effect of the outcome of these matters on our financial statements cannot be predicted with certainty as any such effect depends on the amount and timing of the resolution of such matters. Other than the litigation described below, we do not believe that any of our outstanding litigation would have a material adverse effect on our business or prospects.

Environmental. We are subject to a wide variety of laws and regulations concerning the protection of the environment, both with respect to the operations at many of our properties and with respect to remediating environmental conditions that may exist at our own or other properties. We accrue for environmental expenses resulting from existing conditions that relate to past operations when the costs are probable and reasonably estimable.

In the acquisition agreement pursuant to which a predecessor to Tyco sold our businesses to a previous owner in August 1999, Tyco agreed to indemnify us and our affiliates, among other things, for all “Excluded Liabilities.” Excluded Liabilities include, among other things, substantially all liabilities relating to the time prior to August 1999, including environmental liabilities. The indemnity survives indefinitely. Tyco’s indemnity does not cover liabilities to the extent caused by us or the operation of our businesses after August 1999, nor does it cover liabilities arising with respect to businesses or sites acquired after August 1999. Since 2007, Tyco has engaged in multiple corporate restructurings, split-offs and divestitures. While none of these transactions directly affects the indemnification obligations of the Tyco indemnitors under the 1999 acquisition agreement, the result of such transactions is that the assets of, and control over, such Tyco indemnitors has changed. Should any of these Tyco indemnitors become financially unable or fail to comply with the terms of the indemnity, we may be responsible for such obligations or liabilities.

In September 1987, we implemented an Administrative Consent Order (“ACO”) for our Burlington, New Jersey property, which was required under the New Jersey Environmental Cleanup Responsibility Act (now known as the Industrial Site Recovery Act). The ACO required soil and ground-water cleanup, and we completed, and received final approval on, the soil cleanup required by the ACO. We retained this property related to the sale of our former U.S. Pipe segment. We expect ground-water issues as well as issues associated with the demolition of former manufacturing facilities at this site will continue and remediation by us could be required. Long-term ground-water monitoring may also be required, but we do not know how long such monitoring would be required and do not believe monitoring or further remediation costs, if any, will have a material adverse effect on any of our financial statements.

On July 13, 2010, Rohcan Investments Limited, the former owner of property leased by Mueller Canada Ltd. and located in Milton, Ontario, filed suit against Mueller Canada Ltd. and its directors seeking C$10.0 million in damages arising from the defendants’ alleged environmental contamination of the property and breach of lease. Mueller Canada Ltd. leased the property from 1988 through 2008. We are pursuing indemnification from a former owner for certain potential liabilities that are alleged in this lawsuit, and we have accrued for other liabilities not covered by indemnification. On December 7, 2011, the Court denied the plaintiff’s motion for summary judgment.

The purchaser of U.S. Pipe has been identified as a “potentially responsible party” (“PRP”) under the Comprehensive Environmental Response, Compensation and Liability Act (“Superfund”) in connection with a former manufacturing facility operated by U.S. Pipe that was in the vicinity of a Superfund site located in North Birmingham, Alabama. Under the terms of the acquisition agreement relating to the sale of U.S. Pipe, we agreed to indemnify the purchaser for certain environmental liabilities, including those arising out of the former manufacturing site in North Birmingham. Accordingly, the purchaser tendered the matter to us for indemnification, which we accepted. Ultimate liability for the site will depend on many factors that have not yet been determined, including the determination of EPA’s remediation costs, the number and financial viability of the other PRPs (there are four other PRPs currently) and the determination of the final allocation of the costs among the PRPs, if any. Accordingly, because the amount of such costs cannot be reasonably estimated at this time, no amounts had been accrued for this matter at September 30, 2015.

Walter Energy. Each member of the Walter Energy consolidated group, which included us through December 14, 2006, is jointly and severally liable for the federal income tax liability of each other member of the consolidated group for any year in which it is a member of the group at any time during such year. Accordingly, we could be liable in the event any such federal income tax liability is incurred, and not discharged, by any other member of the Walter Energy consolidated group for any period during which we were included in the Walter Energy consolidated group.

Walter Energy effectively controlled all of our tax decisions for periods during which we were a member of the Walter Energy consolidated group for federal income tax purposes and certain combined, consolidated or unitary state and local income tax groups. Under the terms of an income tax allocation agreement between us and Walter Energy, dated May 26, 2006, we generally compute our tax liability on a stand-alone basis, but Walter Energy has sole authority to respond to and conduct all tax proceedings (including tax audits) relating to our federal income and combined state tax returns, to file all such tax returns on our behalf and to determine the amount of our liability to (or entitlement to payment from) Walter Energy for such previous periods.

A dispute exists with the IRS regarding federal income taxes allegedly owed by the Walter Energy consolidated group from multiple tax years. According to Walter Energy's quarterly report on Form 10-Q filed with the SEC on November 5, 2015 (the "Walter Form 10-Q"), at September 30, 2015, Walter Energy had $33.0 million of accruals for unrecognized tax benefits on the matters subject to disposition. Walter Energy has stated it believes that all of its current and prior tax filing positions have substantial merit and intends to vigorously defend any tax claims asserted. In addition, Walter Energy stated in the Walter Form 10-Q that it believes that it has sufficient accruals to address any claims, including interest and penalties, and does not believe that any potential difference between the final settlements and the amounts accrued will have a material effect on its financial position, but such potential difference could be material to results of its operations in a future reporting period.

Walter Energy filed a petition for reorganization under Chapter 11 of the U.S. Bankruptcy Code in July 2015. We are currently monitoring the filing inasmuch as we could be liable for all or a portion of this federal income tax liability if it is incurred, and not discharged, for any period during which we were included in the Walter Energy consolidated group.

In accordance with the income tax allocation agreement, Walter Energy used certain tax assets of one of our predecessors in its calendar 2006 tax return for which payment to us is required. The income tax allocation agreement only requires Walter Energy to make the payment upon realization of this tax benefit by receiving a refund or otherwise offsetting taxes due. Walter Energy currently owes us $11.6 million that is payable pending completion of an IRS audit of Walter Energy’s 2006 tax year and the related refund of tax from that year. As a result of the aforementioned Chapter 11 petition, we recorded a provision for doubtful accounts of $11.6 million in the quarter ended June 30, 2015. During the quarter ended September 30, 2015, we wrote off this receivable.

Indemnifications. We are a party to contracts in which it is common for us to agree to indemnify third parties for certain liabilities that arise out of or relate to the subject matter of the contract. In some cases, this indemnity extends to related liabilities arising from the negligence of the indemnified parties, but usually excludes any liabilities caused by gross negligence or willful misconduct. We cannot estimate the potential amount of future payments under these indemnities until events arise that would trigger a liability under the indemnities.

Additionally, in connection with the sale of assets and the divestiture of businesses, such as the divestiture of our U.S. Pipe segment, we may agree to indemnify buyers and related parties for certain losses or liabilities incurred by these parties with respect to: (i) the representations and warranties made by us to these parties in connection with the sale and (ii) liabilities related to the pre-closing operations of the assets or business sold. Indemnities related to pre-closing operations generally include certain environmental and tax liabilities and other liabilities not assumed by these parties in the transaction.

Indemnities related to the pre-closing operations of sold assets or businesses normally do not represent additional liabilities to us, but simply serve to protect these parties from potential liability associated with our obligations existing at the time of the sale. As with any liability, we have accrued for those pre-closing obligations that are considered probable and reasonably estimable. Should circumstances change, increasing the likelihood of payments related to a specific indemnity, we will accrue a liability when future payment is probable and the amount is reasonably estimable.

Other Matters. Anvil is in a dispute with Victaulic Company (“Victaulic”) regarding two patents held by Victaulic, U.S. Patent 7,086,131 (the “131 Patent”) and U.S. Patent 7,712,796 (the “796 Patent” and collectively with the 131 Patent, the “U.S. Patents”), which Anvil believes are invalid. The U.S. Patents potentially relate to a coupling product currently manufactured and marketed by Anvil. Anvil filed multiple reexamination requests with the U.S. Patent and Trademark Office (the “PTO”) regarding the U.S. Patents, and the PTO granted the requests. Although the PTO examiner initially invalidated most of the claims of the 796 Patent, the PTO examiner affirmed the validity of the 796 Patent in September 2014. In April 2015, the PTO examiner invalidated the original claim of the 131 Patent but found several claims added during reexamination that appear substantially similar to those included in the 796 Patent patentable. The PTO examiners’ decisions with respect to the U.S. Patents have been appealed by Anvil and Victaulic. Relatedly, Anvil and Victaulic are engaged in lawsuits in the U.S. District Court for the Northern District of Georgia and in the Federal Court of Toronto, Ontario, Canada. The Georgia District Court litigation has been stayed pending the final outcome of the ongoing reexaminations of the U.S. Patents by the PTO. Although Anvil intends to continue to vigorously contest the validity of the U.S. Patents, as well as Victaulic’s related patents in Canada, and to defend itself against any counterclaims made by Victaulic, the probability of a favorable or unfavorable outcome with respect to these proceedings is unknown. Any number of potential outcomes is possible due to the multiple claims associated with the proceedings, each of which is in different stages and subject to appeal. Further, there are a number of highly complex factual and technical issues involved, and it is uncertain whether a favorable or unfavorable result with respect to a particular ruling or proceeding will impact the other matters in controversy. Accordingly, we have not recorded any accrual with respect to these proceedings and a range of liability is not reasonably estimable.

We are party to a number of other lawsuits arising in the ordinary course of business, including product liability cases for products manufactured by us or third parties. We provide for costs relating to these matters when a loss is probable and the amount is reasonably estimable. Administrative costs related to these matters are expensed as incurred. The effect of the outcome of these matters on our future financial statements cannot be predicted with certainty as any such effect depends on the amount and timing of the resolution of such matters. While the results of litigation cannot be predicted with certainty, we believe that the final outcome of such other litigation is not likely to have a materially adverse effect on our business or prospects.

Operating Leases. We maintain operating leases primarily for equipment and facilities. Rent expense was $10.4 million, $9.3 million and $8.4 million for 2015, 2014 and 2013, respectively. Future minimum payments under non-cancellable operating leases are $6.7 million, $5.5 million, $3.0 million, $1.7 million and $0.6 million during 2016, 2017, 2018, 2019 and 2020, respectively. Total minimum payments due beyond 2020 are $1.9 million.