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Acquisitions - Additional Information (Detail) - USD ($) $ in Millions |  |  | 4 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Sep. 05, 2017 | Aug. 08, 2016 | Dec. 31, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Business Acquisition [Line Items] |  |  |  |  |  |
Aggregate cash purchase price, net of cash acquired |  |  |  | $ 43.1 | $ 90.8 |
Acquired intangible assets, amortization period, in years |  |  |  | 12 years |  |
Operating earnings |  |  |  | $ 577.9 | $ 515.0 | $ 452.9
Aquasana |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Percentage of ownership interest acquired |  | 100.00% |  |  |  |
Aggregate cash purchase price, net of cash acquired |  | $ 85.1 |  |  |  |
Cash acquired from business acquisition |  | 1.9 |  |  |  |
Contingent consideration and holdback |  | 1.7 |  |  |  |
Acquisition-related costs |  | 1.2 |  |  |  |
Acquired intangible assets |  | 30.0 |  |  |  |
Aquasana | Trade Names |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Acquired intangible assets, not subject to amortization |  | 21.5 |  |  |  |
Aquasana | Customer Lists |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Acquired intangible assets, subject to amortization |  | $ 8.3 |  |  |  |
Acquired intangible assets, amortization period, in years |  | 10 years |  |  |  |
Aquasana | Patents |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Acquired intangible assets, subject to amortization |  | $ 0.2 |  |  |  |
Acquired intangible assets, amortization period, in years |  | 5 years |  |  |  |
Hague |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Percentage of ownership interest acquired | 100.00% |  |  |  |  |
Aggregate cash purchase price, net of cash acquired | $ 43.1 |  |  |  |  |
Cash acquired from business acquisition | 4.1 |  |  |  |  |
Contingent consideration and holdback | $ 1.5 |  | $ 2.0 | $ 2.0 |  |
Contingent consideration, conditions measurement period | 2 years |  |  |  |  |
Acquisition-related costs | $ 0.2 |  | 0.2 |  |  |
Acquired intangible assets | 12.8 |  |  |  |  |
Revenues |  |  | 8.6 |  |  |
Pre tax earnings |  |  | 2.0 |  |  |
Operating earnings |  |  | $ 2.2 |  |  |
Hague | Maximum |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Contingent consideration and holdback | 2.0 |  |  |  |  |
Hague | Trade Names |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Acquired intangible assets, not subject to amortization | 1.1 |  |  |  |  |
Hague | Customer Lists |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |
Acquired intangible assets, subject to amortization | $ 11.7 |  |  |  |  |
Acquired intangible assets, amortization period, in years | 18 years |  |  |  |  |

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- Definition Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275 + Details
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- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e1043-128460 + Details
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- Definition Amount of liability recognized arising from contingent consideration in a business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 35 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 25 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476 + Details
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- Definition This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463 + Details
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- Definition Amount of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit, acquired at the acquisition date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472 + Details
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- Definition Amount of intangible assets, excluding goodwill, acquired at the acquisition date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472 + Details
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- Definition The cash inflow associated with the acquisition of business during the period (for example, cash that was held by the acquired business). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585 + Details
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