Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

+ Details

Name:	invest_DerivativeNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

+ Details

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

- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (a),(c),(d),(e)

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959

+ Details

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

- Details

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

- Details

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

- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions.

+ References

No definition available.

+ Details

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

- Definition

Represents the percentage of projected intercompany purchase transactions hedged for the next twelve months by forward exchange contracts.

+ References

No definition available.

+ Details

Name:	wts_PercentageOfProjectedIntercompanyPurchaseTransactionsHedgedForNextTwelveMonthsByForwardExchangeContracts
Namespace Prefix:	wts_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Financial Instruments (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative instruments
Percentage of projected intercompany purchases hedged by forward exchange contracts	50.00%
Period of projected intercompany purchase transactions	12 months
Amount of Gain or (Loss) Recognized in Income on Derivatives
Income (loss) from derivatives recorded to other expense (income), net in statement of operations	$ 0.1	$ 0.1	$ 0.6
Forward exchange contracts \| Purchased contracts \| Low end of range
Derivative instruments
Notional amount	1.0
Forward exchange contracts \| Purchased contracts \| High end of range
Derivative instruments
Notional amount	10.0
Forward exchange contracts \| Non designated
Derivative instruments
Notional amount	1.0
Swap
Derivative instruments
Derivative outstanding	$ 0	$ 0