Name:	us-gaap_LossContingenciesLineItems
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Amount of loss contingency liability.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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Period Type:	instant

Amount of loss contingency liability expected to be resolved within one year or the normal operating cycle, if longer.

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Amount of loss contingency liability expected to be resolved after one year or beyond the normal operating cycle, if longer.

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Amount of increase (decrease) in loss contingency liability.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

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Data Type:	xbrli:monetaryItemType
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Number of defendants named in a legal action.

No definition available.

Name:	us-gaap_LossContingencyNumberOfDefendants
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Amount of receivable related to a loss contingency accrual that is expected to be collected within one year or the normal operating cycle, if longer. For example, an insurance recovery receivable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12053-110248

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Data Type:	xbrli:monetaryItemType
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Amount of cash inflow from the collection of receivables related to a loss contingency.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Amount of cash outflow for contributions to the class action fund, reducing loss contingency liability.

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Amount of cash outflow for counsel fees reducing loss contingency liability.

No definition available.

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Namespace Prefix:	wts_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of cash outflow for notice and claims administrator reducing loss contingency liability.

No definition available.

Name:	wts_LossContingencyAccrualNoticeAndClaimsAdministratorPayments
Namespace Prefix:	wts_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of estimated insurance receivable related to a loss contingency accrual. For example, an estimated insurance recovery receivable.

No definition available.

Name:	wts_LossContingencyEstimatedInsuranceReceivable
Namespace Prefix:	wts_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Reflects the proposed estimated amount of loss from the specified contingency.

No definition available.

Name:	wts_LossContingencyProposedEstimateOfPossibleLoss
Namespace Prefix:	wts_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents the number of separate putative class action complaints.

No definition available.

Name:	wts_NumberOfClassActionComplaints
Namespace Prefix:	wts_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Period for Payment of Remaining Liability

No definition available.

Name:	wts_PeriodForPaymentOfRemainingLiability
Namespace Prefix:	wts_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Amount of total proposed judgement or settlement awarded to (against) the entity in respect of litigation.

No definition available.