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Summary of Significant Accounting Policies (Details) $ in Millions |  | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | --- | ---
Jul. 07, 2016 USD ($) | Dec. 31, 2018 USD ($) | Sep. 30, 2018 USD ($) | Dec. 31, 2017 USD ($) reporting_unit | Dec. 31, 2018 USD ($) segments | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Jan. 01, 2019 USD ($) | Dec. 31, 2015 USD ($)
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Defined Benefit Plan, Other Cost (Credit) |  |  |  |  |  | $ 0.3 | $ 0.2 |  |
Proceeds from Divestiture of Businesses |  |  |  |  | $ 10.0 | 123.1 | 40.6 |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Number of Reporting Units | reporting_unit |  |  |  | 3 |  |  |  |  |
Goodwill |  | $ 887.9 |  | $ 884.9 | 887.9 | 884.9 |  |  | $ 871.6
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) |  |  |  |  | 0.0 |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Total impairment charges |  |  |  |  | 0.0 | 19.9 | 0.2 |  |
Revenue Recognition [Abstract] |  |  |  |  |  |  |  |  |
Accounts Receivable, Gross, Current |  | $ 128.6 |  | 127.0 | 128.6 | 127.0 |  |  |
Revenue Recognition, Sales Discounts and Rebates |  |  |  |  | 8.1 | 9.1 | 8.7 |  |
Revenue Recognition, Sales Returns, Reserve for Sales Returns |  |  |  |  | $ 7.7 | 8.5 | 5.1 |  |
Number of reportable segments | segments |  |  |  |  | 2 |  |  |  |
Document Fiscal Year Focus |  |  |  |  | 2018 |  |  |  |
Noncash Investing and Financing Items [Abstract] |  |  |  |  |  |  |  |  |
Purchases of property and equipment included in accounts payable |  |  |  |  | $ 7.1 | 8.5 | 1.5 |  |
Maximum |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Operating Lease, Liability |  |  |  |  |  |  |  | $ 45.0 |
Operating Lease, Right-of-Use Asset |  |  |  |  |  |  |  | 42.0 |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  |  |  |  | 15 years |  |  |  |
Minimum |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Operating Lease, Liability |  |  |  |  |  |  |  | 40.0 |
Operating Lease, Right-of-Use Asset |  |  |  |  |  |  |  | $ 37.0 |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  |  |  |  | 5 years |  |  |  |
Percentage of fair value in excess of carrying amount |  | 50.00% |  |  | 50.00% |  |  |  |
Buildings and improvements | Maximum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 31 years 6 months |  |  |  |
Buildings and improvements | Minimum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 5 years |  |  |  |
Machinery and equipment | Maximum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 7 years |  |  |  |
Machinery and equipment | Minimum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 1 year 6 months |  |  |  |
Furniture and fixtures | Maximum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 5 years |  |  |  |
Furniture and fixtures | Minimum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 2 years |  |  |  |
Vehicles |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 3 years |  |  |  |
Software and software development costs | Maximum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 5 years |  |  |  |
Software and software development costs | Minimum |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Property, plant and equipment, useful life |  |  |  |  | 3 years |  |  |  |
Speaker and Receiver Product Line | Discontinued Operations, Disposed of by Sale [Member] |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Proceeds from Divestiture of Businesses | $ 40.6 |  |  |  |  |  |  |  |
Patents |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Finite-Lived Intangible Assets, Period Increase (Decrease) |  |  |  |  |  |  | 0.0 |  |
Patents | Maximum |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  |  |  |  | 10 years |  |  |  |
Patents | Minimum |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Finite-Lived Intangible Asset, Useful Life |  |  |  |  | 7 years |  |  |  |
Impairment of Fixed and Other Assets |  |  |  |  |  |  |  |  |
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Total impairment charges |  |  |  |  |  |  | 0.5 |  |
Precision Devices |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Goodwill |  | $ 28.0 |  | 25.0 | $ 28.0 | 25.0 |  |  | 25.0
Precision Devices | Timing Device Business [Member] | Discontinued Operations, Disposed of by Sale [Member] |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Proceeds from Divestiture of Businesses |  |  |  |  | 135.1 |  |  |  |
Audio |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Goodwill |  | 859.9 |  | $ 859.9 | 859.9 | 859.9 |  |  | $ 846.6
Property, Plant and Equipment [Abstract] |  |  |  |  |  |  |  |  |
Total impairment charges |  |  |  |  | 0.0 | $ 21.3 | $ 0.5 |  |
Prepaid Expenses and Other Current Assets [Member] | Precision Devices | Timing Device Business [Member] |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Proceeds from Divestiture of Businesses |  |  | $ 10.0 |  |  |  |  |  |
Mobile Consumer Electronics [Member] |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Goodwill |  | 722.1 |  |  | 722.1 |  |  |  |
Hearing Health Technologies [Member] |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Goodwill |  | 137.8 |  |  | 137.8 |  |  |  |
Capacitors [Member] |  |  |  |  |  |  |  |  |
Goodwill and Intangible Assets [Abstract] |  |  |  |  |  |  |  |  |
Goodwill |  | 28.0 |  |  | $ 28.0 |  |  |  |
Internal Revenue Service (IRS) [Member] |  |  |  |  |  |  |  |  |
Accounting Policies [Line Items] |  |  |  |  |  |  |  |  |
Increase (Decrease) in Income Taxes |  | 17.8 |  |  |  |  |  |  |
Unrecognized Tax Benefits, Period Increase (Decrease) |  | $ 36.0 | $ 36.0 |  |  |  |  |  |

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