COMMITMENTS AND CONTINGENCIES	6 Months Ended
Sep. 30, 2017
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	(O) COMMITMENTS AND CONTINGENCIES We have certain deductible limits under our workers’ compensation and liability insurance policies for which reserves are established based on the undiscounted estimated costs of known and anticipated claims. We have entered into standby letter of credit agreements relating to workers’ compensation and auto and general liability self-insurance. At September 30, 2017, we had contingent liabilities under these outstanding letters of credit of approximately $9.4 million. In the ordinary course of business, we execute contracts involving indemnifications that are standard in the industry and indemnifications specific to a transaction such as sale of a business. These indemnifications may include claims relating to any of the following: environmental and tax matters; intellectual property rights; governmental regulations and employment-related matters; customer, supplier, and other commercial contractual relationships; construction contracts and financial matters. While the maximum amount to which the Company may be exposed under such agreements cannot be estimated, it is the opinion of management that these indemnifications are not expected to have a material adverse effect on our consolidated financial position, results of operations or cash flows. We currently have no outstanding guarantees. We are currently contingently liable for performance under $21.1 million in performance bonds required by certain states and municipalities, and their related agencies. The bonds are principally for certain reclamation obligations and mining permits. We have indemnified the underwriting insurance company against any exposure under the performance bonds. In our past experience, no material claims have been made against these financial instruments. EPA Notice of Violation On October 5, 2010, Region IX of the EPA issued a Notice of Violation and Finding of Violation (“NOV”) alleging violations by our subsidiary, Nevada Cement Company (“NCC”), of the Clean Air Act (“CAA”). The NOV alleged that NCC made certain physical changes to its facility in the 1990s without first obtaining permits required by the Prevention of Significant Deterioration requirements and Title V permit requirements of the CAA. The EPA also alleged that NCC has failed to submit to the EPA since 2002 certain reports required by the National Emissions Standard for Hazardous Air Pollutants General Provisions and the Portland Cement Manufacturing Industry Standards. On March 12, 2014, the EPA Region IX issued a second NOV to NCC. The second NOV was materially similar to the 2010 NOV except that it alleged violations of the new source performance standards (“NSPS”) for Portland cement plants. The NOVs stated that the EPA may seek penalties although it did not propose or assess any specific level of penalties or specify what relief the EPA would seek for the alleged violations. In January 2017, NCC entered into a Consent Decree in which NCC agreed to install at its Fernley, Nevada plant certain emission control equipment (selective non-catalytic reduction) to reduce nitrous oxide emissions and to pay a penalty of $0.6 million. NCC also agreed to replace two existing vehicles with two new vehicles with more efficient Tier 4 engines. Under the terms of the Consent Decree, NCC will complete the installation of the emission control equipment and vehicle replacement in approximately 2 years. It is anticipated that the investment in the new emission control equipment and vehicles will cost approximately $3.0 million. In the Consent Decree NCC denies all allegations set forth in the NOVs and the Complaint which was filed simultaneously with the entry of the Consent Decree, and the Consent Decree resolves all such claims by the government. The Consent Decree was signed by the EPA and the US Department of Justice and lodged in US District Court for the District of Nevada in May 2017. On October 4, 2017, the Consent Decree was entered by the Court and NCC paid the penalty in early October. Domestic Wallboard Antitrust Litigation Since late December 2012, several purported class action lawsuits were filed in various United States District Courts, including the Eastern District of Pennsylvania, Western District of North Carolina and the Northern District of Illinois, against the Company’s subsidiary, American Gypsum Company LLC (“American Gypsum”), alleging that the defendant wallboard manufacturers conspired to fix the price for drywall sold in the United States in violation of federal antitrust laws and, in some cases related provisions of state law. The complaints allege that the defendant wallboard manufacturers conspired to increase prices through the announcement and implementation of coordinated price increases, output restrictions, and other restraints of trade, including the elimination of individual “job quote” pricing. In addition to American Gypsum, the defendants in these lawsuits included CertainTeed Corp. (“Certainteed”), USG Corporation and United States Gypsum (together “USG”), New NGC, Inc. (“New NGC”), Lafarge North America (“Lafarge”), Temple Inland Inc. (“TIN”) and PABCO Building Products LLC (“PABCO”). On April 8, 2013, the Judicial Panel on Multidistrict Litigation (“JPML”) transferred and consolidated all related cases to the Eastern District of Pennsylvania for coordinated pretrial proceedings. On June 24, 2013, the direct and indirect purchaser plaintiffs filed consolidated amended class action complaints. The direct purchasers’ complaint added the Company as a defendant. The plaintiffs in the consolidated class action complaints assert claims on behalf of purported classes of direct purchasers or end users of wallboard from January 1, 2012 to the present for unspecified monetary damages (including treble damages) and in some cases injunctive relief. On July 29, 2013, the Company and American Gypsum answered the complaints, denying all allegations that they conspired to increase the price of drywall and asserting affirmative defenses to the plaintiffs’ claims. In 2014, USG and TIN entered into agreements with counsel representing the direct and indirect purchaser classes pursuant to which they agreed to settle all claims against them. Under the terms of its settlement agreement, USG agreed to pay $48.0 million to resolve the direct and indirect purchaser class actions. In its settlement agreement, TIN agreed to pay $7.0 million to resolve the direct and indirect purchaser class actions. On August 20, 2015, the court entered orders finally approving USG and TIN’s settlements with the direct and indirect purchaser plaintiffs. Following completion of the initial discovery, the Company and remaining co-defendants moved for summary judgment. On February 18, 2016, the court denied the Company’s motion for summary judgment and granted judgment in favor of Certainteed. On June 16, 2016, Lafarge entered into an agreement with counsel for the direct purchaser class under which it agreed to settle all claims against it for $23.0 million. The court entered an order finally approving this settlement on December 7, 2016. On July 28, 2016, Lafarge entered into an agreement with counsel representing the indirect purchaser class under which it agreed to settle all claims against it for $5.2 million. Indirect purchaser plaintiffs filed a motion for preliminary approval of this settlement in September 2016. On July 14, 2016, the Company’s motion for permission to appeal the summary judgment decision to the U.S. Court of Appeals for the Third Circuit was denied. Direct purchaser plaintiffs and indirect purchaser plaintiffs filed their motions for class certification on August 3, 2016 and October 12, 2016, respectively. The Court held an evidentiary hearing on the direct purchaser plaintiffs’ motion for class certification in April 2017 and held a hearing on indirect purchaser plaintiffs’ motion for class certification in June 2017. On August 23, 2017, the court granted the direct purchaser plaintiffs’ motion for class certification and certified a class consisting of all persons or entities that purchased paper-backed gypsum wallboard in the United States from January 1, 2012 through January 31, 2013 directly from American Gypsum, the Company, Lafarge, New NGC, PABCO, USG, and/or L&W Supply Corporation (which was a subsidiary of USG Corporation during the class period). On August 24, 2017, the court denied the indirect purchaser plaintiffs’ motion for class certification. On September 6, 2017, American Gypsum, the Company, New NGC, and PABCO filed a petition with the U.S. Court of Appeals for the Third Circuit seeking interlocutory appeal of the district court’s decision granting the direct purchaser plaintiffs’ motion for class certification under Federal Rule of Civil Procedure 23(f). On September 7, 2017, the indirect purchaser plaintiffs filed a petition with the Third Circuit appealing the district court’s denial of their motion for class certification. The Third Circuit denied the indirect purchaser plaintiff’s petition on October 12, 2017; the defendants’ petition remains pending before the Third Circuit. On September 7, 2017, the indirect purchaser plaintiffs also filed a proposal to file a motion for class certification for a class consisting of persons and entities who purchased drywall manufactured by American Gypsum, USG, New NGC, Lafarge, TIN, and PABCO from The Home Depot, Inc., Lowe’s Companies, Inc., or Menards Inc. during the period from January 1, 2012 through January 31, 2013. On September 6, 2017, American Gypsum, the Company, New NGC, and PABCO moved for the entry of partial summary judgment in their favor with respect to the direct purchaser and indirect purchaser plaintiffs’ claims that TIN and non-defendant Georgia-Pacific LLC participated in the alleged conspiracy. The plaintiffs moved to strike the motion for partial summary judgment on September 18, 2017. In the direct purchaser class action, if the petition currently before the Third Circuit appealing direct purchasers class certification is not granted, we expect that a trial date may be set in the near future. We intend to continue to defend against these claims vigorously. In addition, we plan to commence preparations for trial and may from time to time engage in settlement and other discussions with direct purchaser plaintiffs, if we conclude that such discussions have the potential to result in an appropriate resolution of this action. At this point, we are not able to predict the likely outcome of a trial or any settlement discussions; however, an adverse outcome in either scenario could have a material adverse effect on our financial position or results of operations. On March 17, 2015, a group of homebuilders filed a complaint against the defendants, including American Gypsum, based upon the same conduct alleged in the consolidated class action complaints. On March 24, 2015, the JPML transferred this action to the multidistrict litigation already pending in the Eastern District of Pennsylvania. Following the transfer, the homebuilder plaintiffs filed two amended complaints, on December 14, 2015 and March 25, 2016. As a result of settlements reached with TIN and Lafarge, the homebuilder plaintiffs voluntarily dismissed their claims against TIN and Lafarge on June 6 and June 24, 2016, respectively. On January 31, 2017, the plaintiffs voluntarily dismissed their claims against CertainTeed. Discovery in this lawsuit is ongoing. At this stage, we are unable to estimate the amount of any reasonably possible loss or range of reasonably possible losses for the anti-trust lawsuits. In June 2015, American Gypsum and an employee received grand jury subpoenas from the United States District Court for the Western District of North Carolina seeking information regarding an investigation of the gypsum drywall industry by the Antitrust Division of the Department of Justice. We believe the investigation, although a separate proceeding, is related to the same subject matter at issue in the litigation described above and we intend to fully cooperate with government officials. Given its preliminary nature, we are currently unable to determine the ultimate outcome of such investigation.

(O) COMMITMENTS AND CONTINGENCIES

We have certain deductible limits under our workers’ compensation and liability insurance policies for which reserves are established based on the undiscounted estimated costs of known and anticipated claims. We have entered into standby letter of credit agreements relating to workers’ compensation and auto and general liability self-insurance. At September 30, 2017, we had contingent liabilities under these outstanding letters of credit of approximately $9.4 million.

In the ordinary course of business, we execute contracts involving indemnifications that are standard in the industry and indemnifications specific to a transaction such as sale of a business. These indemnifications may include claims relating to any of the following: environmental and tax matters; intellectual property rights; governmental regulations and employment-related matters; customer, supplier, and other commercial contractual relationships; construction contracts and financial matters. While the maximum amount to which the Company may be exposed under such agreements cannot be estimated, it is the opinion of management that these indemnifications are not expected to have a material adverse effect on our consolidated financial position, results of operations or cash flows. We currently have no outstanding guarantees.

We are currently contingently liable for performance under $21.1 million in performance bonds required by certain states and municipalities, and their related agencies. The bonds are principally for certain reclamation obligations and mining permits. We have indemnified the underwriting insurance company against any exposure under the performance bonds. In our past experience, no material claims have been made against these financial instruments.

EPA Notice of Violation

On October 5, 2010, Region IX of the EPA issued a Notice of Violation and Finding of Violation (“NOV”) alleging violations by our subsidiary, Nevada Cement Company (“NCC”), of the Clean Air Act (“CAA”). The NOV alleged that NCC made certain physical changes to its facility in the 1990s without first obtaining permits required by the Prevention of Significant Deterioration requirements and Title V permit requirements of the CAA. The EPA also alleged that NCC has failed to submit to the EPA since 2002 certain reports required by the National Emissions Standard for Hazardous Air Pollutants General Provisions and the Portland Cement Manufacturing Industry Standards. On March 12, 2014, the EPA Region IX issued a second NOV to NCC. The second NOV was materially similar to the 2010 NOV except that it alleged violations of the new source performance standards (“NSPS”) for Portland cement plants. The NOVs stated that the EPA may seek penalties although it did not propose or assess any specific level of penalties or specify what relief the EPA would seek for the alleged violations. In January 2017, NCC entered into a Consent Decree in which NCC agreed to install at its Fernley, Nevada plant certain emission control equipment (selective non-catalytic reduction) to reduce nitrous oxide emissions and to pay a penalty of $0.6 million. NCC also agreed to replace two existing vehicles with two new vehicles with more efficient Tier 4 engines. Under the terms of the Consent Decree, NCC will complete the installation of the emission control equipment and vehicle replacement in approximately 2 years. It is anticipated that the investment in the new emission control equipment and vehicles will cost approximately $3.0 million. In the Consent Decree NCC denies all allegations set forth in the NOVs and the Complaint which was filed simultaneously with the entry of the Consent Decree, and the Consent Decree resolves all such claims by the government. The Consent Decree was signed by the EPA and the US Department of Justice and lodged in US District Court for the District of Nevada in May 2017. On October 4, 2017, the Consent Decree was entered by the Court and NCC paid the penalty in early October.

Domestic Wallboard Antitrust Litigation

Since late December 2012, several purported class action lawsuits were filed in various United States District Courts, including the Eastern District of Pennsylvania, Western District of North Carolina and the Northern District of Illinois, against the Company’s subsidiary, American Gypsum Company LLC (“American Gypsum”), alleging that the defendant wallboard manufacturers conspired to fix the price for drywall sold in the United States in violation of federal antitrust laws and, in some cases related provisions of state law. The complaints allege that the defendant wallboard manufacturers conspired to increase prices through the announcement and implementation of coordinated price increases, output restrictions, and other restraints of trade, including the elimination of individual “job quote” pricing. In addition to American Gypsum, the defendants in these lawsuits included CertainTeed Corp. (“Certainteed”), USG Corporation and United States Gypsum (together “USG”), New NGC, Inc. (“New NGC”), Lafarge North America (“Lafarge”), Temple Inland Inc. (“TIN”) and PABCO Building Products LLC (“PABCO”). On April 8, 2013, the Judicial Panel on Multidistrict Litigation (“JPML”) transferred and consolidated all related cases to the Eastern District of Pennsylvania for coordinated pretrial proceedings.

On June 24, 2013, the direct and indirect purchaser plaintiffs filed consolidated amended class action complaints. The direct purchasers’ complaint added the Company as a defendant. The plaintiffs in the consolidated class action complaints assert claims on behalf of purported classes of direct purchasers or end users of wallboard from January 1, 2012 to the present for unspecified monetary damages (including treble damages) and in some cases injunctive relief. On July 29, 2013, the Company and American Gypsum answered the complaints, denying all allegations that they conspired to increase the price of drywall and asserting affirmative defenses to the plaintiffs’ claims.

In 2014, USG and TIN entered into agreements with counsel representing the direct and indirect purchaser classes pursuant to which they agreed to settle all claims against them. Under the terms of its settlement agreement, USG agreed to pay $48.0 million to resolve the direct and indirect purchaser class actions. In its settlement agreement, TIN agreed to pay $7.0 million to resolve the direct and indirect purchaser class actions. On August 20, 2015, the court entered orders finally approving USG and TIN’s settlements with the direct and indirect purchaser plaintiffs. Following completion of the initial discovery, the Company and remaining co-defendants moved for summary judgment. On February 18, 2016, the court denied the Company’s motion for summary judgment and granted judgment in favor of Certainteed. On June 16, 2016, Lafarge entered into an agreement with counsel for the direct purchaser class under which it agreed to settle all claims against it for $23.0 million. The court entered an order finally approving this settlement on December 7, 2016. On July 28, 2016, Lafarge entered into an agreement with counsel representing the indirect purchaser class under which it agreed to settle all claims against it for $5.2 million. Indirect purchaser plaintiffs filed a motion for preliminary approval of this settlement in September 2016. On July 14, 2016, the Company’s motion for permission to appeal the summary judgment decision to the U.S. Court of Appeals for the Third Circuit was denied.

Direct purchaser plaintiffs and indirect purchaser plaintiffs filed their motions for class certification on August 3, 2016 and October 12, 2016, respectively. The Court held an evidentiary hearing on the direct purchaser plaintiffs’ motion for class certification in April 2017 and held a hearing on indirect purchaser plaintiffs’ motion for class certification in June 2017. On August 23, 2017, the court granted the direct purchaser plaintiffs’ motion for class certification and certified a class consisting of all persons or entities that purchased paper-backed gypsum wallboard in the United States from January 1, 2012 through January 31, 2013 directly from American Gypsum, the Company, Lafarge, New NGC, PABCO, USG, and/or L&W Supply Corporation (which was a subsidiary of USG Corporation during the class period). On August 24, 2017, the court denied the indirect purchaser plaintiffs’ motion for class certification. On September 6, 2017, American Gypsum, the Company, New NGC, and PABCO filed a petition with the U.S. Court of Appeals for the Third Circuit seeking interlocutory appeal of the district court’s decision granting the direct purchaser plaintiffs’ motion for class certification under Federal Rule of Civil Procedure 23(f). On September 7, 2017, the indirect purchaser plaintiffs filed a petition with the Third Circuit appealing the district court’s denial of their motion for class certification. The Third Circuit denied the indirect purchaser plaintiff’s petition on October 12, 2017; the defendants’ petition remains pending before the Third Circuit. On September 7, 2017, the indirect purchaser plaintiffs also filed a proposal to file a motion for class certification for a class consisting of persons and entities who purchased drywall manufactured by American Gypsum, USG, New NGC, Lafarge, TIN, and PABCO from The Home Depot, Inc., Lowe’s Companies, Inc., or Menards Inc. during the period from January 1, 2012 through January 31, 2013.

On September 6, 2017, American Gypsum, the Company, New NGC, and PABCO moved for the entry of partial summary judgment in their favor with respect to the direct purchaser and indirect purchaser plaintiffs’ claims that TIN and non-defendant Georgia-Pacific LLC participated in the alleged conspiracy. The plaintiffs moved to strike the motion for partial summary judgment on September 18, 2017.

In the direct purchaser class action, if the petition currently before the Third Circuit appealing direct purchasers class certification is not granted, we expect that a trial date may be set in the near future. We intend to continue to defend against these claims vigorously. In addition, we plan to commence preparations for trial and may from time to time engage in settlement and other discussions with direct purchaser plaintiffs, if we conclude that such discussions have the potential to result in an appropriate resolution of this action. At this point, we are not able to predict the likely outcome of a trial or any settlement discussions; however, an adverse outcome in either scenario could have a material adverse effect on our financial position or results of operations.

On March 17, 2015, a group of homebuilders filed a complaint against the defendants, including American Gypsum, based upon the same conduct alleged in the consolidated class action complaints. On March 24, 2015, the JPML transferred this action to the multidistrict litigation already pending in the Eastern District of Pennsylvania. Following the transfer, the homebuilder plaintiffs filed two amended complaints, on December 14, 2015 and March 25, 2016. As a result of settlements reached with TIN and Lafarge, the homebuilder plaintiffs voluntarily dismissed their claims against TIN and Lafarge on June 6 and June 24, 2016, respectively. On January 31, 2017, the plaintiffs voluntarily dismissed their claims against CertainTeed. Discovery in this lawsuit is ongoing.

At this stage, we are unable to estimate the amount of any reasonably possible loss or range of reasonably possible losses for the anti-trust lawsuits.

In June 2015, American Gypsum and an employee received grand jury subpoenas from the United States District Court for the Western District of North Carolina seeking information regarding an investigation of the gypsum drywall industry by the Antitrust Division of the Department of Justice. We believe the investigation, although a separate proceeding, is related to the same subject matter at issue in the litigation described above and we intend to fully cooperate with government officials. Given its preliminary nature, we are currently unable to determine the ultimate outcome of such investigation.