XML 54 R7.htm IDEA: XBRL DOCUMENT
v2.4.1.9

CONSOLIDATED STATEMENTS OF CAPITAL STOCK AND LONG-TERM DEBT (Parenthetical) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013
Common Stock, Shares Authorized | 40,000,000 us-gaap_CommonStockSharesAuthorized | 40,000,000 us-gaap_CommonStockSharesAuthorized
Common Stock, Shares Outstanding | 16,124,000 us-gaap_CommonStockSharesOutstanding | 15,963,000 us-gaap_CommonStockSharesOutstanding
Preferred Stock, Shares Authorized | 126,000 us-gaap_PreferredStockSharesAuthorized | 126,000 us-gaap_PreferredStockSharesAuthorized
Preferred Stock, Shares Outstanding | 24,000 us-gaap_PreferredStockSharesOutstanding | 28,000 us-gaap_PreferredStockSharesOutstanding
Amortizing Secured Note, due December 20, 2021 [Member] |  |
Due date of debt | Dec. 20, 2021 |
Interest rate | 8.05%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = us-gaap_SecuredDebtMember |
Amortizing Secured Note, due May 19, 2028 [Member] |  |
Due date of debt | May 19, 2028 |
Interest rate | 6.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_SecuredDebt1Member |
Amortizing Secured Note, due August 25, 2030 [Member] |  |
Due date of debt | Aug. 25, 2030 |
Interest rate | 6.44%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_SecuredDebt2Member |
Amortizing Secured Note, due September 19, 2031 [Member] |  |
Due date of debt | Sep. 19, 2031 |
Interest rate | 6.46%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_SecuredDebt3Member |
State Revolving Trust Note, due December 31, 2022 [Member] |  |
Due date of debt | Dec. 31, 2022 |
Interest rate | 4.22%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNoteMember |
State Revolving Trust Note, due January 25, 2027 [Member] |  |
Due date of debt | Jan. 25, 2027 |
Interest rate | 3.49%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote2Member |
State Revolving Trust Note, due May 1, 2025 [Member] |  |
Due date of debt | May 01, 2025 |
Interest rate | 3.60%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote1Member |
State Revolving Trust Note, due March 1, 2026 [Member] |  |
Due date of debt | Mar. 01, 2026 |
Interest rate | 3.30%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote9Member |
State Revolving Trust Note, due December 1, 2026 [Member] |  |
Due date of debt | Dec. 01, 2026 |
Interest rate | 4.03%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote3Member |
State Revolving Trust Bond 4.00% to 5.00%, due August 1, 2021 [Member] |  |
Due date of debt | Aug. 01, 2021 |
Interest rate - minimum | 4.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustBondMember |
Interest rate - maximum | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustBondMember |
State Revolving Trust Bond 0.00%, due August 1, 2021 [Member] |  |
Due date of debt | Aug. 01, 2021 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustBond1Member |
State Revolving Trust Note, due July 1, 2028 [Member] |  |
Due date of debt | Jul. 01, 2028 |
Interest rate | 3.64%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote4Member |
State Revolving Trust Note, due January 1, 2028 [Member] |  |
Due date of debt | Jan. 01, 2028 |
Interest rate | 3.64%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote5Member |
State Revolving Trust Note, due August 1, 2031 [Member] |  |
Due date of debt | Aug. 01, 2031 |
Interest rate | 3.45%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote6Member |
Amortizing Secured Note, due April 20, 2029 [Member] |  |
Due date of debt | Apr. 20, 2029 |
Interest rate | 6.59%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_SecuredDebt4Member |
Amortizing Secured Note 7.05%, due January 20, 2030 [Member] |  |
Due date of debt | Jan. 20, 2030 |
Interest rate | 7.05%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_SecuredDebt5Member |
Amortizing Secured Note 5.69%, due January 20, 2030 [Member] |  |
Due date of debt | Jan. 20, 2030 |
Interest rate | 5.69%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_SecuredDebt6Member |
Amortizing Secured Note, due April 20, 2040 [Member] |  |
Due date of debt | Apr. 20, 2040 |
State Revolving Trust Note, due July 1, 2031 [Member] |  |
Due date of debt | Jul. 01, 2031 |
Interest rate | 3.75%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote7Member |
State Revolving Trust Note, due November 30, 2030 [Member] |  |
Due date of debt | Nov. 30, 2030 |
Interest rate | 3.75%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_StateRevolvingTrustNote8Member |
First Mortgage Bonds - Series X [Member] |  |
Due date of debt | Sep. 01, 2018 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage1Member |
First Mortgage Bonds - Series Y [Member] |  |
Due date of debt | Sep. 01, 2018 |
Interest rate - minimum | 4.25%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage2Member |
Interest rate - maximum | 4.63%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage2Member |
First Mortgage Bonds - Series Z [Member] |  |
Due date of debt | Sep. 01, 2019 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage3Member |
First Mortgage Bonds - Series AA [Member] |  |
Due date of debt | Sep. 01, 2019 |
Interest rate - minimum | 5.25%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage4Member |
Interest rate - maximum | 5.75%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage4Member |
First Mortgage Bonds - Series BB [Member] |  |
Due date of debt | Sep. 01, 2021 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage5Member |
First Mortgage Bonds - Series CC [Member] |  |
Due date of debt | Sep. 01, 2021 |
Interest rate - minimum | 4.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage6Member |
Interest rate - maximum | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage6Member |
First Mortgage Bonds - Series EE [Member] |  |
Due date of debt | Aug. 01, 2023 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage8Member |
First Mortgage Bonds - Series FF [Member] |  |
Due date of debt | Aug. 01, 2024 |
Interest rate - minimum | 3.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage9Member |
Interest rate - maximum | 5.50%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage9Member |
First Mortgage Bonds - Series GG [Member] |  |
Due date of debt | Aug. 01, 2026 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage10Member |
First Mortgage Bonds - Series HH [Member] |  |
Due date of debt | Aug. 01, 2026 |
Interest rate - minimum | 4.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage11Member |
Interest rate - maximum | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage11Member |
First Mortgage Bonds - Series II [Member] |  |
Due date of debt | Aug. 01, 2024 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage12Member |
First Mortgage Bonds - Series JJ [Member] |  |
Due date of debt | Aug. 01, 2027 |
Interest rate - minimum | 3.40%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage13Member |
Interest rate - maximum | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage13Member |
First Mortgage Bonds - Series KK [Member] |  |
Due date of debt | Aug. 01, 2028 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage14Member |
First Mortgage Bonds - Series LL [Member] |  |
Due date of debt | Aug. 01, 2028 |
Interest rate - minimum | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage15Member |
Interest rate - maximum | 5.50%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage15Member |
First Mortgage Bonds - Series MM [Member] |  |
Due date of debt | Aug. 01, 2030 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage16Member |
First Mortgage Bonds - Series NN [Member] |  |
Due date of debt | Aug. 01, 2030 |
Interest rate - minimum | 3.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage17Member |
Interest rate - maximum | 4.375%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage17Member |
First Mortgage Bonds - Series OO [Member] |  |
Due date of debt | Aug. 01, 2031 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage18Member |
First Mortgage Bonds - Series PP [Member] |  |
Due date of debt | Aug. 01, 2031 |
Interest rate - minimum | 2.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage19Member |
Interest rate - maximum | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage19Member |
First Mortgage Bonds - Series QQ [Member] |  |
Due date of debt | Oct. 01, 2023 |
Interest rate | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage20Member |
First Mortgage Bonds - Series RR [Member] |  |
Due date of debt | Oct. 01, 2038 |
Interest rate | 3.80%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage21Member |
First Mortgage Bonds - Series SS [Member] |  |
Due date of debt | Oct. 01, 2047 |
Interest rate | 4.25%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage22Member |
First Mortgage Bonds - Series TT [Member] |  |
Due date of debt | Aug. 01, 2032 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage23Member |
First Mortgage Bonds - Series UU [Member] |  |
Due date of debt | Aug. 01, 2032 |
Interest rate - minimum | 3.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage24Member |
Interest rate - maximum | 3.25%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage24Member |
First Mortgage Bonds - Series VV [Member] |  |
Due date of debt | Aug. 01, 2033 |
Interest rate | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = msex_FirstMortgage25Member |
First Mortgage Bonds - Series WW [Member] |  |
Due date of debt | Aug. 01, 2033 |
Interest rate - minimum | 3.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage26Member |
Interest rate - maximum | 5.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum / us-gaap_DebtInstrumentAxis = msex_FirstMortgage26Member |
Convertible Preferred Stock $7.00 Series |  |
Preferred Stock, Shares Outstanding | 10,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = us-gaap_ConvertiblePreferredStockMember | 14,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = us-gaap_ConvertiblePreferredStockMember
Convertible Preferred Stock $8.00 Series [Member] |  |
Preferred Stock, Shares Outstanding | 3,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = msex_ConvertiblePreferredStock1Member | 3,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = msex_ConvertiblePreferredStock1Member
Nonredeemable Preferred Stock $7.00 Series |  |
Preferred Stock, Shares Outstanding | 1,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemablePreferredStockMember | 1,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemablePreferredStockMember
Nonredeemable Preferred Stock $4.75 Series [Member] |  |
Preferred Stock, Shares Outstanding | 10,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = msex_NonredeemablePreferredStock1Member | 10,000 us-gaap_PreferredStockSharesOutstanding / us-gaap_StatementClassOfStockAxis = msex_NonredeemablePreferredStock1Member

X
- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. + 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 210.5-02.29) -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 30 -Article 5 + Details
Name: | us-gaap_CommonStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 + Details
Name: | us-gaap_CommonStockSharesOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: 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(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Maximum contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: 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(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: 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(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: 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(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. + 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 210.5-02.28) -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 29 -Article 5 + Details
Name: | us-gaap_PreferredStockSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. + 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 210.5-02.28) -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 29 -Article 5 + Details
Name: | us-gaap_PreferredStockSharesOutstanding
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage10Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage11Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage12Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage13Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage14Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage15Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage16Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage17Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage18Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage19Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage20Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage21Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage22Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage23Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage24Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage25Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage26Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage5Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage6Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage8Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_FirstMortgage9Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_SecuredDebt1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_SecuredDebt2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_SecuredDebt3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_SecuredDebt4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_SecuredDebt5Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_SecuredDebt6Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_SecuredDebt7Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustBond1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustBondMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote5Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote6Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote7Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote8Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNote9Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=msex_StateRevolvingTrustNoteMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_SecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=msex_ConvertiblePreferredStock1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=msex_NonredeemablePreferredStock1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_ConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_NonredeemablePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |