Basis of Presentation and Nature of Operations	3 Months Ended
Mar. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation and Nature of Operations	Basis of Presentation and Nature of Operations Aerojet Rocketdyne Holdings, Inc. ("Aerojet Rocketdyne Holdings" or the "Company") has prepared the accompanying unaudited condensed consolidated financial statements, including the accounts of the Company and its 100% owned and majority owned subsidiaries, in accordance with the instructions to Form 10-Q. The December 31, 2021, condensed consolidated balance sheet was derived from audited financial statements, but does not include all of the disclosures required by accounting principles generally accepted in the United States of America ("GAAP"). These interim financial statements should be read in conjunction with the financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021. Certain reclassifications have been made to financial information for prior years to conform to the current year’s presentation. The Company believes the accompanying unaudited condensed consolidated financial statements reflect all adjustments, including normal recurring accruals, necessary for a fair statement of its financial position, results of operations, and cash flows for the periods presented. All significant intercompany balances and transactions have been eliminated in consolidation. The preparation of the unaudited condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates. In addition, the operating results for interim periods may not be indicative of the results of operations for a full year. The Company’s operations are organized into two segments: Aerospace and Defense — includes the operations of the Company’s wholly-owned subsidiary Aerojet Rocketdyne, Inc. ("Aerojet Rocketdyne"), a leading technology-based designer, developer and manufacturer of aerospace and defense products and systems for the United States ("U.S.") government, including the Department of Defense ("DoD"), the National Aeronautics and Space Administration ("NASA"), and major aerospace and defense prime contractors. Real Estate — includes the activities of the Company’s wholly-owned subsidiary Easton Development Company, LLC ("Easton") related to the re-zoning, entitlement, sale, and leasing of the Company’s excess real estate assets. The fiscal year of the Company's subsidiary, Aerojet Rocketdyne, ends on the last Saturday in December. A detailed description of the Company’s significant accounting policies can be found in the Company’s most recent Annual Report on Form 10-K for the year ended December 31, 2021. Revision of Previously Issued Consolidated Financial Statements During the three months ended March 31, 2022, the Company identified an error in its accounting for income taxes associated with its 2.25% Convertible Senior Notes ("2¼% Notes"). Upon issuance of the 2¼% Notes in 2016, the Company did not record the applicable deferred tax liability associated with the conversion option that had been recorded in other capital, which resulted in an overstatement of other capital, an understatement of deferred tax liabilities and an error in income tax expense in subsequent periods. The Company evaluated the errors and concluded that the errors were not material, either individually or in aggregate, to its current or previously issued consolidated financial statements. To correct the immaterial errors, the Company has revised its previously issued consolidated financial statements as of December 31, 2021 and 2020, and for each of the three years ended December 31, 2021, 2020, and 2019, and its unaudited condensed consolidated financial statements as of and for the quarters and year-to-date periods ended March 31, 2021, June 30, 2021, and September 30, 2021. The revision of the historical consolidated financial statements also includes the correction of an immaterial misclassification in its unaudited condensed consolidated balance sheet as of December 31, 2020. Accordingly, the accompanying financial statements and relevant footnotes to the unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been revised to correct for such immaterial errors. See Note 12 for additional information. The Company will present the revision of its previously issued consolidated financial statements as of December 31, 2021, and for the years ended December 31, 2021 and 2020, in connection with the future filing of its 2022 Annual Report on Form 10-K. Additionally, the Company will present the revision of its previously issued condensed consolidated financial statements as of and for the three and six months ended June 30, 2021, and as of and for the three and nine months ended September 30, 2021, in connection with the future filings of its Quarterly Reports on Form 10-Q. Terminated Merger Agreement On December 20, 2020, the Company entered into an Agreement and Plan of Merger (the "Merger Agreement") with Lockheed Martin Corporation ("Lockheed Martin") and Mizar Sub, Inc., a wholly-owned subsidiary of Lockheed Martin ("Merger Sub"), pursuant to which each share of common stock of the Company would have been automatically converted into the right to receive cash in an amount equal to $51.00 per share, adjusted from $56.00 following the payment of a one-time cash dividend of $5.00 per share paid in March 2021 (the "Pre-Closing Dividend") and the Company would have become a wholly-owned subsidiary of Lockheed Martin (the "Merger"). On January 25, 2022, the Federal Trade Commission ("FTC") filed a complaint against the Company and Lockheed Martin in the FTC’s administrative court and a complaint in U.S. federal court seeking a preliminary injunction to stop the deal pending an administrative trial (the "FTC Litigation"). On February 13, 2022, Lockheed Martin notified the Company that it had elected to terminate the Merger Agreement. On February 14, 2022, pursuant to the parties’ joint motion, the administrative complaint and the U.S. federal court complaint were dismissed. Coronavirus ("COVID-19") Pandemic During the three months ended March 31, 2022, the Company’s financial results and operations were not materially adversely impacted by the COVID-19 pandemic. The extent to which the Company’s future financial results could be impacted by the COVID-19 pandemic depends on future developments that are highly uncertain and cannot be predicted at this time. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of the date of issuance of this Quarterly Report on Form 10-Q. These estimates may change, as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions. Recently Issued Accounting Pronouncements In August 2020, the Financial Accounting Standards Board issued guidance which simplifies the accounting for convertible instruments. This guidance eliminates certain models that require separate accounting for embedded conversion features, in certain cases. Additionally, among other changes, the guidance eliminates certain of the conditions for equity classification for contracts in an entity’s own equity. The guidance also requires entities to use the if-converted method for all convertible instruments in the diluted earnings per share calculation and include the effect of share settlement for instruments that may be settled in cash or shares, except for certain liability-classified share-based payment awards. The Company adopted the new guidance as of January 1, 2022, using the modified retrospective approach resulting in the following adjustment (i) a decrease of $1.9 million in deferred tax liabilities, (ii) a decrease of $5.6 million in other capital, (iii) a decrease of $1.0 million in retained earnings, and (iv) an increase of $8.5 million in debt.

Aerojet Rocketdyne Holdings, Inc. ("Aerojet Rocketdyne Holdings" or the "Company") has prepared the accompanying unaudited condensed consolidated financial statements, including the accounts of the Company and its 100% owned and majority owned subsidiaries, in accordance with the instructions to Form 10-Q. The December 31, 2021, condensed consolidated balance sheet was derived from audited financial statements, but does not include all of the disclosures required by accounting principles generally accepted in the United States of America ("GAAP"). These interim financial statements should be read in conjunction with the financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021. Certain reclassifications have been made to financial information for prior years to conform to the current year’s presentation.

The Company believes the accompanying unaudited condensed consolidated financial statements reflect all adjustments, including normal recurring accruals, necessary for a fair statement of its financial position, results of operations, and cash flows for the periods presented. All significant intercompany balances and transactions have been eliminated in consolidation. The preparation of the unaudited condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the amounts reported in the unaudited condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates. In addition, the operating results for interim periods may not be indicative of the results of operations for a full year.

Aerospace and Defense — includes the operations of the Company’s wholly-owned subsidiary Aerojet Rocketdyne, Inc. ("Aerojet Rocketdyne"), a leading technology-based designer, developer and manufacturer of aerospace and defense products and systems for the United States ("U.S.") government, including the Department of Defense ("DoD"), the National Aeronautics and Space Administration ("NASA"), and major aerospace and defense prime contractors.

Real Estate — includes the activities of the Company’s wholly-owned subsidiary Easton Development Company, LLC ("Easton") related to the re-zoning, entitlement, sale, and leasing of the Company’s excess real estate assets.

A detailed description of the Company’s significant accounting policies can be found in the Company’s most recent Annual Report on Form 10-K for the year ended December 31, 2021.

During the three months ended March 31, 2022, the Company identified an error in its accounting for income taxes associated with its 2.25% Convertible Senior Notes ("2¼% Notes"). Upon issuance of the 2¼% Notes in 2016, the Company did not record the applicable deferred tax liability associated with the conversion option that had been recorded in other capital, which resulted in an overstatement of other capital, an understatement of deferred tax liabilities and an error in income tax expense in subsequent periods. The Company evaluated the errors and concluded that the errors were not material, either individually or in aggregate, to its current or previously issued consolidated financial statements.

To correct the immaterial errors, the Company has revised its previously issued consolidated financial statements as of December 31, 2021 and 2020, and for each of the three years ended December 31, 2021, 2020, and 2019, and its unaudited condensed consolidated financial statements as of and for the quarters and year-to-date periods ended March 31, 2021, June 30, 2021, and September 30, 2021. The revision of the historical consolidated financial statements also includes the correction of an immaterial misclassification in its unaudited condensed consolidated balance sheet as of December 31, 2020.

Accordingly, the accompanying financial statements and relevant footnotes to the unaudited condensed consolidated financial statements in this Quarterly Report on Form 10-Q have been revised to correct for such immaterial errors. See Note 12 for additional information. The Company will present the revision of its previously issued consolidated financial statements as of December 31, 2021, and for the years ended December 31, 2021 and 2020, in connection with the future filing of its 2022 Annual Report on Form 10-K. Additionally, the Company will present the revision of its previously issued condensed consolidated financial statements as of and for the three and six months ended June 30, 2021, and as of and for the three and nine months ended September 30, 2021, in connection with the future filings of its Quarterly Reports on Form 10-Q.

On December 20, 2020, the Company entered into an Agreement and Plan of Merger (the "Merger Agreement") with Lockheed Martin Corporation ("Lockheed Martin") and Mizar Sub, Inc., a wholly-owned subsidiary of Lockheed Martin ("Merger Sub"), pursuant to which each share of common stock of the Company would have been automatically converted into the right to receive cash in an amount equal to $51.00 per share, adjusted from $56.00 following the payment of a one-time cash dividend of $5.00 per share paid in March 2021 (the "Pre-Closing Dividend") and the Company would have become a wholly-owned subsidiary of Lockheed Martin (the "Merger").

On January 25, 2022, the Federal Trade Commission ("FTC") filed a complaint against the Company and Lockheed Martin in the FTC’s administrative court and a complaint in U.S. federal court seeking a preliminary injunction to stop the deal pending an administrative trial (the "FTC Litigation"). On February 13, 2022, Lockheed Martin notified the Company that it had elected to

During the three months ended March 31, 2022, the Company’s financial results and operations were not materially adversely impacted by the COVID-19 pandemic. The extent to which the Company’s future financial results could be impacted by the COVID-19 pandemic depends on future developments that are highly uncertain and cannot be predicted at this time. The Company is not aware of any specific event or circumstance that would require an update to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of the date of issuance of this Quarterly Report on Form 10-Q. These estimates may change, as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions.