XML 57 R39.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Commitments and Contingent Liabilities (Schedule of Purchased Water Costs) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Purchased Water |  |  |
Untreated | $ 2,600 | $ 2,500 | $ 2,400
Treated | 3,200 | 3,100 | 3,100
Total Costs | $ 5,800 | $ 5,600 | $ 5,500

X
- Definition Purchased Water + References No definition available. + Details
Name: | msex_CostOfPurchasedWaterAbstract
Namespace Prefix: | msex_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Refers to cost of treated water during the period. + References No definition available. + Details
Name: | msex_CostOfTreatedWater
Namespace Prefix: | msex_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Refers to cost of untreated water during the period. + References No definition available. + Details
Name: | msex_CostOfUntreatedWater
Namespace Prefix: | msex_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cost of water purchased, may include any water related assessment. If water is bought on a unit volume basis, would also be considered as commodity costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_CostOfPurchasedWater
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration