COMMITMENTS AND CONTINGENCIES	6 Months Ended
Sep. 30, 2018
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, 2018, we had contingent liabilities under these outstanding letters of credit of approximately $7.8 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 the 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, management believes these indemnifications will not 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 $27.7 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. 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 and the Company’s subsidiary, American Gypsum Company LLC (American Gypsum), alleging that the defendant wallboard manufacturers conspired to fix the price of drywall sold in the United States in violation of federal antitrust laws, and in some cases related provisions of state law. In addition to American Gypsum, the defendants in these lawsuits included certain other wallboard manufacturers. These cases were subsequently transferred and consolidated to the Eastern District of Pennsylvania for coordinated pretrial proceedings. The plaintiffs in the consolidated class action complaints asserted 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. The Company and American Gypsum denied all allegations that they conspired to increase the price of drywall and asserted affirmative defenses to the plaintiffs’ claims. 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. 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). In addition, on August 24, 2017, the court denied the indirect purchaser’s motion for class certification. On December 29, 2017, American Gypsum and the Company, as well as New NGC and PABCO, which are not affiliated with the Company, entered into a settlement agreement (the Direct Purchaser Settlement Agreement) with counsel representing the direct purchaser class to settle all claims made against the Company, American Gypsum, New NGC, and PABCO in the direct purchaser class action. The Direct Purchaser Settlement Agreement, in which the Company and American Gypsum deny all wrongdoing, also includes releases by the participating class members of the Company and American Gypsum as well as their subsidiaries, affiliates, and other related parties, for the time period from January 1, 2012, through the date of execution of the Direct Purchaser Settlement Agreement. On January 5, 2018, American Gypsum, New NGC, and PABCO entered into a settlement agreement (the Indirect Purchaser Settlement Agreement) with counsel representing the indirect purchaser class to settle all claims against American Gypsum, New NGC, and PABCO in the indirect purchaser class action. The Indirect Purchaser Settlement Agreement was approved by the District Court on October 26, 2018. Under the Direct and Indirect Purchaser Settlement Agreements, the Company and American Gypsum agreed to pay a total of approximately $39.1 million in cash to settle the claims against them. These claims were accrued at the time of the settlements, and during March 2018 we deposited approximately $38.8 million into a qualified settlement fund. The amount accrued under the Direct Purchaser Settlement Agreement was paid in July 2018 after approval by the District Court. In March 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. In March 2015, the Judicial Panel on Multidistrict Litigation (JPML) transferred this action to the multidistrict litigation already pending in the Eastern District of Pennsylvania. Effective May 8, 2018, American Gypsum and the homebuilder plaintiffs entered into a settlement agreement (the Homebuilder Settlement Agreement) to settle all claims made against American Gypsum. The Homebuilder Settlement Agreement, in which American Gypsum denies all wrongdoing, includes releases by the homebuilder plaintiffs of American Gypsum as well as its subsidiaries, affiliates, and other related parties, for the time period prior to and including the date of execution of the Homebuilder Settlement Agreement. Under the Homebuilder Settlement Agreement, American Gypsum agreed to pay a total of $6.0 million in cash to settle the claims against it. At March 31, 2018, we accrued the total amount of this settlement, and this amount was paid in May 2018. 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, was related to the same subject matter at issue in the litigation described above. On August 24, 2018, the Antitrust Division notified us that the investigation has been closed.

(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, 2018, we had contingent liabilities under these outstanding letters of credit of approximately $7.8 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 the 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, management believes these indemnifications will not 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 $27.7 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.

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 and the Company’s subsidiary, American Gypsum Company LLC (American Gypsum), alleging that the defendant wallboard manufacturers conspired to fix the price of drywall sold in the United States in violation of federal antitrust laws, and in some cases related provisions of state law. In addition to American Gypsum, the defendants in these lawsuits included certain other wallboard manufacturers. These cases were subsequently transferred and consolidated to the Eastern District of Pennsylvania for coordinated pretrial proceedings.

The plaintiffs in the consolidated class action complaints asserted 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. The Company and American Gypsum denied all allegations that they conspired to increase the price of drywall and asserted affirmative defenses to the plaintiffs’ claims.

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.

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). In addition, on August 24, 2017, the court denied the indirect purchaser’s motion for class certification.

On December 29, 2017, American Gypsum and the Company, as well as New NGC and PABCO, which are not affiliated with the Company, entered into a settlement agreement (the Direct Purchaser Settlement Agreement) with counsel representing the direct purchaser class to settle all claims made against the Company, American Gypsum, New NGC, and PABCO in the direct purchaser class action. The Direct Purchaser Settlement Agreement, in which the Company and American Gypsum deny all wrongdoing, also includes releases by the participating class members of the Company and American Gypsum as well as their subsidiaries, affiliates, and other related parties, for the time period from January 1, 2012, through the date of execution of the Direct Purchaser Settlement Agreement. On January 5, 2018, American Gypsum, New NGC, and PABCO entered into a settlement agreement (the Indirect Purchaser Settlement Agreement) with counsel representing the indirect purchaser class to settle all claims against American Gypsum, New NGC, and PABCO in the indirect purchaser class action. The Indirect Purchaser Settlement Agreement was approved by the District Court on October 26, 2018. Under the Direct and Indirect Purchaser Settlement Agreements, the Company and American Gypsum agreed to pay a total of approximately $39.1 million in cash to settle the claims against them. These claims were accrued at the time of the settlements, and during March 2018 we deposited approximately $38.8 million into a qualified settlement fund. The amount accrued under the Direct Purchaser Settlement Agreement was paid in July 2018 after approval by the District Court.

In March 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. In March 2015, the Judicial Panel on Multidistrict Litigation (JPML) transferred this action to the multidistrict litigation already pending in the Eastern District of Pennsylvania. Effective May 8, 2018, American Gypsum and the homebuilder plaintiffs entered into a settlement agreement (the Homebuilder Settlement Agreement) to settle all claims made against American Gypsum. The Homebuilder Settlement Agreement, in which American Gypsum denies all wrongdoing, includes releases by the homebuilder plaintiffs of American Gypsum as well as its subsidiaries, affiliates, and other related parties, for the time period prior to and including the date of execution of the Homebuilder Settlement Agreement. Under the Homebuilder Settlement Agreement, American Gypsum agreed to pay a total of $6.0 million in cash to settle the claims against it. At March 31, 2018, we accrued the total amount of this settlement, and this amount was paid in May 2018.

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, was related to the same subject matter at issue in the litigation described above. On August 24, 2018, the Antitrust Division notified us that the investigation has been closed.