Business and Organization	12 Months Ended
Sep. 30, 2015
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business and Organization	A. Business and Organization Powell Industries, Inc. (we, us, our, Powell or the Company) was incorporated in the state of Delaware in 2004 as a successor to a Nevada company incorporated in 1968. The Nevada corporation was the successor to a company founded by William E. Powell in 1947, which merged into the Company in 1977. Our major subsidiaries, all of which are wholly owned, include: Powell Electrical Systems, Inc.; Powell (UK) Limited (formerly Switchgear & Instrumentation Limited); Powell Canada Inc. and Powell Industries International, B.V. We develop, design, manufacture and service custom-engineered equipment and systems for the distribution, control and monitoring of electrical energy designed to (1) distribute, control and monitor the flow of electrical energy and (2) provide protection to motors, transformers and other electrically powered equipment. Our principal products include integrated power control room substations (PCRs®), custom-engineered modules, electrical houses (E-Houses), traditional and arc-resistant distribution switchgear and control gear, medium-voltage circuit breakers, monitoring and control communications systems, motor control centers and bus duct systems. These products are designed for application voltages ranging from 480 volts to 38,000 volts and are used in oil and gas refining, offshore oil and gas production, petrochemical, pipeline, terminal, mining and metals, light rail traction power, electric utility, pulp and paper and other heavy industrial markets. Our product scope includes designs tested to meet both U.S. standards (ANSI) and international standards (IEC). We assist customers by providing value-added services such as spare parts, field service inspection, installation, commissioning, modification and repair, retrofit and retrofill components for existing systems and replacement circuit breakers for switchgear that is obsolete or that is no longer produced by the original manufacturer. We seek to establish long-term relationships with the end users of our systems as well as the design and construction engineering firms contracted by those end users. References to Fiscal 2015, Fiscal 2014 and Fiscal 2013 used throughout these Notes to Consolidated Financial Statements relate to our fiscal years ended September 30, 2015, 2014 and 2013, respectively. We previously reported two business segments: Electrical Power Products and Process Control Systems. In January 2014, we sold our wholly owned subsidiary Transdyn Inc. (Transdyn), which was reported in our Process Controls business segment. We have presented the results of these operations as income from discontinued operations, net of tax, for each of the accompanying consolidated statements of operations. While this sale did not result in a material disposition of assets or material reduction to income before income taxes relative to our consolidated financial statements, the revenues, gross profit, income before income taxes and assets of Transdyn comprised a significant majority of those respective amounts previously reported in our Process Control Systems business segment. As we previously reported only two business segments, Electrical Power Products and Process Control Systems, we have removed the presentation of business segments in these Notes to Consolidated Financial Statements. All current and historical financial information presented exclude the financial information for Transdyn or presents it as discontinued operations where applicable. For more information about this disposition, see Note N.

A. Business and Organization

Powell Industries, Inc. (we, us, our, Powell or the Company) was incorporated in the state of Delaware in 2004 as a successor to a Nevada company incorporated in 1968. The Nevada corporation was the successor to a company founded by William E. Powell in 1947, which merged into the Company in 1977. Our major subsidiaries, all of which are wholly owned, include: Powell Electrical Systems, Inc.; Powell (UK) Limited (formerly Switchgear & Instrumentation Limited); Powell Canada Inc. and Powell Industries International, B.V.

We develop, design, manufacture and service custom-engineered equipment and systems for the distribution, control and monitoring of electrical energy designed to (1) distribute, control and monitor the flow of electrical energy and (2) provide protection to motors, transformers and other electrically powered equipment. Our principal products include integrated power control room substations (PCRs®), custom-engineered modules, electrical houses (E-Houses), traditional and arc-resistant distribution switchgear and control gear, medium-voltage circuit breakers, monitoring and control communications systems, motor control centers and bus duct systems. These products are designed for application voltages ranging from 480 volts to 38,000 volts and are used in oil and gas refining, offshore oil and gas production, petrochemical, pipeline, terminal, mining and metals, light rail traction power, electric utility, pulp and paper and other heavy industrial markets. Our product scope includes designs tested to meet both U.S. standards (ANSI) and international standards (IEC). We assist customers by providing value-added services such as spare parts, field service inspection, installation, commissioning, modification and repair, retrofit and retrofill components for existing systems and replacement circuit breakers for switchgear that is obsolete or that is no longer produced by the original manufacturer. We seek to establish long-term relationships with the end users of our systems as well as the design and construction engineering firms contracted by those end users.

References to Fiscal 2015, Fiscal 2014 and Fiscal 2013 used throughout these Notes to Consolidated Financial Statements relate to our fiscal years ended September 30, 2015, 2014 and 2013, respectively.

We previously reported two business segments: Electrical Power Products and Process Control Systems. In January 2014, we sold our wholly owned subsidiary Transdyn Inc. (Transdyn), which was reported in our Process Controls business segment. We have presented the results of these operations as income from discontinued operations, net of tax, for each of the accompanying consolidated statements of operations. While this sale did not result in a material disposition of assets or material reduction to income before income taxes relative to our consolidated financial statements, the revenues, gross profit, income before income taxes and assets of Transdyn comprised a significant majority of those respective amounts previously reported in our Process Control Systems business segment. As we previously reported only two business segments, Electrical Power Products and Process Control Systems, we have removed the presentation of business segments in these Notes to Consolidated Financial Statements. All current and historical financial information presented exclude the financial information for Transdyn or presents it as discontinued operations where applicable. For more information about this disposition, see Note N.