Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

+ References

No definition available.

+ Details

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

- Definition

The percentage points added to the specified reference rate to compute the variable rate on the debt instrument, in addition to the percentage points added regardless of specified reference rate.

+ References

No definition available.

+ Details

Name:	wts_DebtInstrumentBasisSpreadOnVariableRateAdditional
Namespace Prefix:	wts_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the maximum amount of the guarantees available through letters of credit.

+ References

No definition available.

+ Details

Name:	wts_LettersOfCreditMaximumAmount
Namespace Prefix:	wts_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the additional amount of borrowing capacity that may be added under the credit facility.

+ References

No definition available.

+ Details

Name:	wts_LineOfCreditFacilityOptionForAdditionalBorrowingCapacity
Namespace Prefix:	wts_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Financing Arrangements (Details 2) In Millions, unless otherwise specified			0 Months Ended				0 Months Ended			0 Months Ended			0 Months Ended	3 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Feb. 18, 2014 Credit Agreement	Dec. 31, 2014 Credit Agreement USD ($)	Dec. 31, 2014 Credit Agreement EUR (€)	Feb. 18, 2014 Credit Agreement USD ($)	Feb. 18, 2014 Eurocurrency rate loans LIBOR Minimum	Feb. 18, 2014 Eurocurrency rate loans LIBOR Maximum	Feb. 18, 2014 Base rate loans and swing line loans LIBOR	Feb. 18, 2014 Base rate loans and swing line loans LIBOR Minimum	Feb. 18, 2014 Base rate loans and swing line loans LIBOR Maximum	Feb. 18, 2014 Base rate loans and swing line loans Federal funds	Feb. 18, 2014 Base rate loans and swing line loans Prime Rate	Jun. 30, 2013 Senior unsecured notes USD ($)
Credit Agreement
Multi-currency borrowing capacity						$ 500
Term of senior unsecured revolving credit facility			5 years
Potential additional borrowing capacity						500
Sublimit on letters of credit						100
Interest rate added to base rate (as a percent)							0.975%	1.45%		0.00%	0.45%
Interest rate added to base rate (as a percent)									1.00%			0.50%
Variable interest rate basis													prime rate
Unused and available credit under the credit agreement					201.4
Stand-by letters of credit outstanding	23.6	23.6		23.6
Debt outstanding	577.8us-gaap_LongTermDebtNoncurrent	305.5us-gaap_LongTermDebtNoncurrent			275.0
Repayment of debt														$ 75.0