Basis of Presentation (Notes)	6 Months Ended
Basis of Presentation (Notes)	Jun. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Description of Business - Knowles Corporation (NYSE:KN) is a market leader and global provider of advanced micro-acoustic microphones and speakers, audio processing, and precision device solutions, serving the consumer electronics, communications, medtech, defense, electric vehicle, and industrial markets. The Company uses its leading position in SiSonicTM micro-electro-mechanical systems ("MEMS") microphones and strong capabilities in audio processing technologies to optimize audio systems and improve the user experience in mobile, ear, and Internet of Things ("IoT") applications. Knowles is also a leader in acoustic components, high-end capacitors, and radio frequency ("RF") solutions for a diverse set of markets. The Company's focus on the customer, combined with its unique technology, proprietary manufacturing techniques, rigorous testing, and global scale, enable the Company to deliver innovative solutions that optimize the user experience. References to "Knowles," "the Company," "we," "our," and "us" refer to Knowles Corporation and its consolidated subsidiaries. Financial Statement Presentation - The accompanying unaudited interim Consolidated Financial Statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC") for quarterly reports on Form 10-Q and do not include all of the information and note disclosures required by U.S. generally accepted accounting principles (“GAAP” or “U.S. GAAP”) for complete financial statements. These unaudited interim Consolidated Financial Statements should therefore be read in conjunction with the Consolidated Financial Statements and Notes thereto for the year ended December 31, 2020 included in the Company’s Annual Report on Form 10-K. The accompanying unaudited interim Consolidated Financial Statements have been prepared in accordance with U.S. GAAP, which requires management to make estimates and assumptions that affect amounts reported in the Consolidated Financial Statements and accompanying disclosures. Although these estimates are based on management’s best knowledge of current events and actions that the Company may undertake in the future, actual results may differ from those estimates. Management uses historical experience and all available information to make these estimates, including considerations for the impact of the COVID-19 pandemic on the macroeconomic environment. The situation related to the COVID-19 pandemic continues to be complex and rapidly evolving. The Company cannot reasonably estimate the duration of the COVID-19 pandemic or fully ascertain its impact on the Company’s future results and market capitalization, which could adversely impact estimates such as the recoverability of goodwill and long-lived assets and the realizability of deferred tax assets. The unaudited interim Consolidated Financial Statements reflect all adjustments of a normal, recurring nature that are, in the opinion of management, necessary for a fair statement of results for these interim periods. On May 3, 2021, the Company acquired all of the outstanding shares of common stock of Integrated Microwave Corporation ("IMC"), a manufacturer of RF filters. See Note 4. Acquisition for additional information related to the transaction. On February 24, 2020, the Company announced that its Board of Directors had authorized a share repurchase program of up to $100 million of the Company's common stock. The timing and amount of any shares repurchased will be determined by the Company based on its evaluation of market conditions and other factors, and will be made in accordance with applicable securities laws in either the open market or in privately negotiated transactions. The Company is not obligated to purchase any shares under the program, and the program may be suspended or discontinued at any time. The actual timing, number, and share price of shares repurchased will depend on a number of factors, including the market price of the Company’s common stock, general market and economic conditions, and applicable legal requirements. Any shares repurchased will be held as treasury stock. During the six months ended June 30, 2021, the Company repurchased 1,011,124 shares of common stock for a total of $20.0 million. Non-cash Investing Activities - Purchases of property, plant, and equipment included in accounts payable at June 30, 2021 and 2020 were $1.5 million and $3.3 million, respectively. These non-cash amounts are not reflected as outflows to "Additions to property, plant, and equipment" within "Investing Activities" of the Consolidated Statements of Cash Flows for the respective periods.