XML 36 R24.htm IDEA: XBRL DOCUMENT v3.7.0.1

Capitalization (Schedule of Carrying Amount and Fair Value of Bonds) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Carrying Amount [Member]
First Mortgage Bonds	$ 82,453	$ 82,786
Fair Value [Member]
First Mortgage Bonds	$ 84,535	$ 84,821

X

- Definition

Represents the aggregate of the first mortgage bonds reported on the balance sheet at period end measured at fair value by the entity.

+ References

No definition available.

+ Details

Name:	msex_FirstMortgageBondsFairValueDisclosure
Namespace Prefix:	msex_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: