Description of Business (Details)	12 Months Ended
Dec. 31, 2017
Minimum
Length of time the business has been in operation	140 years

Represents the period of time the entity has been in business.

No definition available.

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