XML 47 R37.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Commitments and Contingent Liabilities (Narrative) (Details) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 USD ($) | Sep. 30, 2021 USD ($) | Sep. 30, 2022 USD ($) gal | Sep. 30, 2021 USD ($)
Purchase Commitment, Excluding Long-Term Commitment [Line Items] |  |  |  |
Construction program | $ |  |  | $ 85.0 |
Estimated obligation expenditure | $ |  |  | 26.0 |
Rental expenses under operating leases | $ | $ 0.2 | $ 0.2 | $ 0.6 | $ 0.6
Estimated incremental borrowing rate | (4.03%) |  | (4.03%) |
NJ Water Supply Authority [Member] |  |  |  |
Purchase Commitment, Excluding Long-Term Commitment [Line Items] |  |  |  |
Purchase commitment expiration date of contract |  |  | Nov. 30, 2023 |
Water purchase per commitment | gal |  |  | 27 |
Regulated Water Authority [Member] |  |  |  |
Purchase Commitment, Excluding Long-Term Commitment [Line Items] |  |  |  |
Purchase commitment expiration date of contract |  |  | Feb. 27, 2026 |
Water purchase per commitment | gal |  |  | 3 |
City of Dover [Member] |  |  |  |
Purchase Commitment, Excluding Long-Term Commitment [Line Items] |  |  |  |
Water purchase per commitment | gal |  |  | 15 |

X
- Definition Budgeted construction cost for construction program, next year. + References No definition available. + Details
Name: | msex_BudgetedConstructionCost
Namespace Prefix: | msex_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Estimated incremental borrowing rate. + References No definition available. + Details
Name: | msex_EstimatedIncrementalBorrowingRate
Namespace Prefix: | msex_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Estimated obligation expenditure. + References No definition available. + Details
Name: | msex_Estimatedobligationexpenditure
Namespace Prefix: | msex_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The expiration date of a long-term purchase commitment. + References No definition available. + Details
Name: | msex_LongtermPurchaseCommitmentExpirationDate
Namespace Prefix: | msex_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of units of goods that must be purchased within the specified time period of the agreement to avoid penalties or unfavorable effects on pricing, among other adverse consequences. + References No definition available. + Details
Name: | us-gaap_LongTermPurchaseCommitmentMinimumQuantityRequired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of operating lease income from lease payments paid and payable to lessor. Excludes variable lease payments not included in measurement of lease receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 270 -SubTopic 10 -Section 50 -Paragraph 6A -URI https://asc.fasb.org/extlink&oid=126900988&loc=SL77927221-108306 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 5 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=124258985&loc=SL77919372-209981 + Details
Name: | us-gaap_OperatingLeaseLeaseIncomeLeasePayments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_PurchaseCommitmentExcludingLongtermCommitmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=us-gaap_PurchaseCommitmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=msex_PurchaseCommitment1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PurchaseCommitmentExcludingLongtermCommitmentAxis=msex_PurchaseCommitment2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |