Organization and Basis of Presentation	9 Months Ended
Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Basis of Presentation	Note 1 – Organization and basis of presentation: Organization. We (NYSE American: CIX) are 86% owned by NL Industries, Inc. (NYSE: NL) at September 30, 2019. We manufacture and sell component products (security products and recreational marine components). At September 30, 2019, Valhi, Inc. (NYSE: VHI) owns 83% of NL’s outstanding common stock and a wholly-owned subsidiary of Contran Corporation owns 92% of Valhi’s outstanding common stock. At September 30, 2019, a majority of Contran’s outstanding voting stock is held directly by Lisa K. Simmons and Serena Simmons Connelly and various family trusts established for the benefit of Ms. Simmons and Ms. Connelly and their children and for which Ms. Simmons or Ms. Connelly, as applicable, serves as trustee. In addition, each of Ms. Simmons and Ms. Connelly serves as co-chair of the Contran board of directors. The remainder of Contran’s outstanding voting stock is held by another trust (the “Family Trust”), which was established for the benefit of Ms. Simmons and Ms. Connelly and their children and for which a third-party financial institution serves as trustee. Consequently, at September 30, 2019, Ms. Simmons, Ms. Connelly and the Family Trust may be deemed to control Contran, and therefore may be deemed to indirectly control the wholly-owned subsidiary of Contran, Valhi, NL and us. Basis of presentation. Consolidated in this Quarterly Report are the results of CompX International Inc. and its subsidiaries. The unaudited Condensed Consolidated Financial Statements contained in this Quarterly Report have been prepared on the same basis as the audited Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2018 that we filed with the Securities and Exchange Commission (“SEC”) on February 27, 2019 (the “2018 Annual Report”). In our opinion, we have made all necessary adjustments (which include only normal recurring adjustments) in order to state fairly, in all material respects, our consolidated financial position, results of operations and cash flows as of the dates and for the periods presented. We have condensed the Consolidated Balance Sheet at December 31, 2018 contained in this Quarterly Report as compared to our audited Consolidated Financial Statements at that date, and we have omitted certain information and footnote disclosures (including those related to the Consolidated Balance Sheet at December 31, 2018) normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Our results of operations for the interim periods ended September 30, 2019 may not be indicative of our operating results for the full year. The Condensed Consolidated Financial Statements contained in this Quarterly Report should be read in conjunction with our 2018 Consolidated Financial Statements contained in our 2018 Annual Report. Our operations are reported on a 52 or 53-week year. For presentation purposes, annual and quarterly information in the Condensed Consolidated Financial Statements and accompanying notes are presented as ended September 30, 2018, December 31, 2018 and September 30, 2019. The actual dates of our annual and quarterly periods are September 30, 2018, December 30, 2018 and September 29, 2019, respectively. Unless otherwise indicated, references in this report to “we”, “us” or “our” refer to CompX International Inc. and its subsidiaries, taken as a whole.

Organization and Basis of Presentation

9 Months Ended

Sep. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Note 1 – Organization and basis of presentation:

Organization. We (NYSE American: CIX) are 86% owned by NL Industries, Inc. (NYSE: NL) at September 30, 2019. We manufacture and sell component products (security products and recreational marine components). At September 30, 2019, Valhi, Inc. (NYSE: VHI) owns 83% of NL’s outstanding common stock and a wholly-owned subsidiary of Contran Corporation owns 92% of Valhi’s outstanding common stock. At September 30, 2019, a majority of Contran’s outstanding voting stock is held directly by Lisa K. Simmons and Serena Simmons Connelly and various family trusts established for the benefit of Ms. Simmons and Ms. Connelly and their children and for which Ms. Simmons or Ms. Connelly, as applicable, serves as trustee. In addition, each of Ms. Simmons and Ms. Connelly serves as co-chair of the Contran board of directors. The remainder of Contran’s outstanding voting stock is held by another trust (the “Family Trust”), which was established for the benefit of Ms. Simmons and Ms. Connelly and their children and for which a third-party financial institution serves as trustee. Consequently, at September 30, 2019, Ms. Simmons, Ms. Connelly and the Family Trust may be deemed to control Contran, and therefore may be deemed to indirectly control the wholly-owned subsidiary of Contran, Valhi, NL and us.

Basis of presentation. Consolidated in this Quarterly Report are the results of CompX International Inc. and its subsidiaries. The unaudited Condensed Consolidated Financial Statements contained in this Quarterly Report have been prepared on the same basis as the audited Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2018 that we filed with the Securities and Exchange Commission (“SEC”) on February 27, 2019 (the “2018 Annual Report”). In our opinion, we have made all necessary adjustments (which include only normal recurring adjustments) in order to state fairly, in all material respects, our consolidated financial position, results of operations and cash flows as of the dates and for the periods presented. We have condensed the Consolidated Balance Sheet at December 31, 2018 contained in this Quarterly Report as compared to our audited Consolidated Financial Statements at that date, and we have omitted certain information and footnote disclosures (including those related to the Consolidated Balance Sheet at December 31, 2018) normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Our results of operations for the interim periods ended September 30, 2019 may not be indicative of our operating results for the full year. The Condensed Consolidated Financial Statements contained in this Quarterly Report should be read in conjunction with our 2018 Consolidated Financial Statements contained in our 2018 Annual Report.

Our operations are reported on a 52 or 53-week year. For presentation purposes, annual and quarterly information in the Condensed Consolidated Financial Statements and accompanying notes are presented as ended September 30, 2018, December 31, 2018 and September 30, 2019. The actual dates of our annual and quarterly periods are September 30, 2018, December 30, 2018 and September 29, 2019, respectively. Unless otherwise indicated, references in this report to “we”, “us” or “our” refer to CompX International Inc. and its subsidiaries, taken as a whole.