Business	12 Months Ended
Dec. 31, 2018
Business [Abstract]
Business	NOTE 1. BUSINESS Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to “AWI,” the “Company,” “we,” “our” and “us” in these notes, we are referring to AWI and its subsidiaries. On August 16, 2018, we acquired the business and assets of Steel Ceilings, Inc. (“Steel Ceilings”), based in Johnstown, Ohio. Steel Ceilings is a manufacturer of aluminum and stainless metal ceilings that include architectural, radiant and security solutions with one manufacturing facility. Steel Ceilings’ operations, and its assets and liabilities, are included as a component of our Architectural Specialties segment. See Note 5 for further information. On May 31, 2018, we acquired the business and assets of Plasterform, Inc. (“Plasterform”), based in Mississauga, Ontario, Canada. Plasterform is a manufacturer of architectural cast ceilings, walls, facades, columns and moldings with one manufacturing facility. Plasterform’s operations, and its assets and liabilities, are included as a component of our Architectural Specialties segment. See Note 5 for further information. On November 17, 2017, we entered into a Share Purchase Agreement (the “Purchase Agreement”) with Knauf International GmbH (“Knauf”), to sell certain subsidiaries comprising our business in Europe, the Middle East and Africa (including Russia) (“EMEA”) and the Pacific Rim, including the corresponding businesses and operations conducted by Worthington Armstrong Venture (“WAVE”), our joint venture with Worthington Industries, Inc. (“Worthington”) in which AWI holds a 50% interest. The consideration paid by Knauf in connection with the sale is $330 million in cash, inclusive of amounts due to WAVE, subject to certain adjustments as provided in the Purchase Agreement, including adjustments based on the economic impact of any required regulatory remedies and a working capital adjustment. On July 18, 2018, we entered into an amendment to the Purchase Agreement, pursuant to which Knauf agreed to irrevocably and unconditionally pay AWI (i) $250 million on August 1, 2018, and (ii) $80 million on September 15, 2018, if, prior to such date (A) any competition condition has not been satisfied, or (B) the closing has not yet occurred. The amendment also provided for the reduction (from a maximum of $35 million to a maximum of $20 million) of potential adjustments to the purchase price consideration for the transaction based on the impact of remedies required to satisfy competition conditions. We received both the $250 million payment and the $80 million payment from Knauf in the third quarter of 2018. Following receipt of these payments, we remitted $70 million to WAVE in partial consideration of the purchase price payable in respect of the business and operations of WAVE under the transaction. WAVE subsequently paid each of AWI and Worthington a dividend of $35 million. We also recorded a $22.4 million payable to WAVE, which is reflected within Accounts Payable and Accrued Expenses. The total consideration payable by AWI to WAVE will be determined following closing in connection with the calculation of the adjustments contemplated by the Purchase Agreement. The transaction was notified for merger control clearance in the European Union (“EU”), Bosnia and Herzegovina, Macedonia, Montenegro, Russia and Serbia, and was cleared unconditionally in Montenegro (February 2018), Serbia (February 2018), Russia (March 2018), Macedonia (July 2018) and Bosnia and Herzegovina (August 2018). On December 7, 2018, the European Commission granted conditional clearance of the transaction, subject to certain commitments intended to address concerns regarding the overlap between the activities of AWI and Knauf, including the divestment by Knauf to a third party of certain mineral fiber and grid businesses and operations in Austria, Estonia, Germany, Ireland, Italy, Latvia, Lithuania, Portugal, Spain, Turkey and the UK. This includes our sales operations in each of the relevant countries, as well as our production facilities, and those of WAVE, located in Team Valley, UK. The terms of the sale of the divestment business by Knauf and the identity of the purchaser are subject to the approval of the European Commission. We continue to work closely with Knauf towards closing and expect the transaction to close by the end of the first half of 2019. The EMEA and Pacific Rim historical financial results have been reflected in AWI’s Consolidated Financial Statements as discontinued operations for all periods presented. In January 2017, we acquired the business and assets of Tectum, Inc. (“Tectum”), based in Newark, Ohio. Tectum is a manufacturer of acoustical ceiling, wall and structural solutions for commercial building applications with two manufacturing facilities. Tectum’s operations and its assets and liabilities have been included as a component of our Architectural Specialties segment. See Note 5 for additional information.

Business

12 Months Ended

Dec. 31, 2018

NOTE 1. BUSINESS

Armstrong World Industries, Inc. (“AWI”) is a Pennsylvania corporation incorporated in 1891. When we refer to “AWI,” the “Company,” “we,” “our” and “us” in these notes, we are referring to AWI and its subsidiaries.

On August 16, 2018, we acquired the business and assets of Steel Ceilings, Inc. (“Steel Ceilings”), based in Johnstown, Ohio. Steel Ceilings is a manufacturer of aluminum and stainless metal ceilings that include architectural, radiant and security solutions with one manufacturing facility. Steel Ceilings’ operations, and its assets and liabilities, are included as a component of our Architectural Specialties segment. See Note 5 for further information.

On May 31, 2018, we acquired the business and assets of Plasterform, Inc. (“Plasterform”), based in Mississauga, Ontario, Canada. Plasterform is a manufacturer of architectural cast ceilings, walls, facades, columns and moldings with one manufacturing facility. Plasterform’s operations, and its assets and liabilities, are included as a component of our Architectural Specialties segment. See Note 5 for further information.

On November 17, 2017, we entered into a Share Purchase Agreement (the “Purchase Agreement”) with Knauf International GmbH (“Knauf”), to sell certain subsidiaries comprising our business in Europe, the Middle East and Africa (including Russia) (“EMEA”) and the Pacific Rim, including the corresponding businesses and operations conducted by Worthington Armstrong Venture (“WAVE”), our joint venture with Worthington Industries, Inc. (“Worthington”) in which AWI holds a 50% interest. The consideration paid by Knauf in connection with the sale is $330 million in cash, inclusive of amounts due to WAVE, subject to certain adjustments as provided in the Purchase Agreement, including adjustments based on the economic impact of any required regulatory remedies and a working capital adjustment.

On July 18, 2018, we entered into an amendment to the Purchase Agreement, pursuant to which Knauf agreed to irrevocably and unconditionally pay AWI (i) $250 million on August 1, 2018, and (ii) $80 million on September 15, 2018, if, prior to such date (A) any competition condition has not been satisfied, or (B) the closing has not yet occurred. The amendment also provided for the reduction (from a maximum of $35 million to a maximum of $20 million) of potential adjustments to the purchase price consideration for the transaction based on the impact of remedies required to satisfy competition conditions. We received both the $250 million payment and the $80 million payment from Knauf in the third quarter of 2018. Following receipt of these payments, we remitted $70 million to WAVE in partial consideration of the purchase price payable in respect of the business and operations of WAVE under the transaction. WAVE subsequently paid each of AWI and Worthington a dividend of $35 million. We also recorded a $22.4 million payable to WAVE, which is reflected within Accounts Payable and Accrued Expenses. The total consideration payable by AWI to WAVE will be determined following closing in connection with the calculation of the adjustments contemplated by the Purchase Agreement.

The transaction was notified for merger control clearance in the European Union (“EU”), Bosnia and Herzegovina, Macedonia, Montenegro, Russia and Serbia, and was cleared unconditionally in Montenegro (February 2018), Serbia (February 2018), Russia (March 2018), Macedonia (July 2018) and Bosnia and Herzegovina (August 2018). On December 7, 2018, the European Commission granted conditional clearance of the transaction, subject to certain commitments intended to address concerns regarding the overlap between the activities of AWI and Knauf, including the divestment by Knauf to a third party of certain mineral fiber and grid businesses and operations in Austria, Estonia, Germany, Ireland, Italy, Latvia, Lithuania, Portugal, Spain, Turkey and the UK. This includes our sales operations in each of the relevant countries, as well as our production facilities, and those of WAVE, located in Team Valley, UK. The terms of the sale of the divestment business by Knauf and the identity of the purchaser are subject to the approval of the European Commission.

We continue to work closely with Knauf towards closing and expect the transaction to close by the end of the first half of 2019. The EMEA and Pacific Rim historical financial results have been reflected in AWI’s Consolidated Financial Statements as discontinued operations for all periods presented.

In January 2017, we acquired the business and assets of Tectum, Inc. (“Tectum”), based in Newark, Ohio. Tectum is a manufacturer of acoustical ceiling, wall and structural solutions for commercial building applications with two manufacturing facilities. Tectum’s operations and its assets and liabilities have been included as a component of our Architectural Specialties segment. See Note 5 for additional information.