Name:	us-gaap_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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=82911808&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=82911808&loc=d3e14557-108349

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of companies joining group for environmental liability notice.

No definition available.

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

Number of companies included in group for environmental liability notice.

No definition available.

Name:	wts_NumberOfCompaniesPartOfGroupForEnvironmentalLiabilityNotice
Namespace Prefix:	wts_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of potentially responsible parties for environmental liability.

No definition available.