XML 40 R26.htm IDEA: XBRL DOCUMENT
v3.20.2

Components of Gas and Electric Operating Revenue (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | $ 83.9 | $ 84.4 | $ 214.3 | $ 235.6
Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 86.7 | 93.1 | 223.7 | 255.0
Rate Adjustment Mechanism Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | (2.8) | (8.7) | (9.4) | (19.4)
Gas Segment |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 33.7 | 32.6 | 103.9 | 119.0
Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 34.5 | 40.3 | 110.9 | 139.5
Gas Segment | Rate Adjustment Mechanism Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | (0.8) | (7.7) | (7.0) | (20.5)
Electric |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 50.2 | 51.8 | 110.4 | 116.6
Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 52.2 | 52.8 | 112.8 | 115.5
Electric | Rate Adjustment Mechanism Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | (2.0) | (1.0) | (2.4) | 1.1
Residential | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 44.5 | 43.4 | 110.0 | 117.9
Residential | Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 14.3 | 15.7 | 45.4 | 54.4
Residential | Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 30.2 | 27.7 | 64.6 | 63.5
C&I | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 39.5 | 46.1 | 106.0 | 124.8
C&I | Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 19.0 | 23.1 | 61.3 | 77.1
C&I | Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 20.5 | 23.0 | 44.7 | 47.7
Other | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 2.7 | 3.6 | 7.7 | 12.3
Other | Gas Segment | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | 1.2 | 1.5 | 4.2 | 8.0
Other | Electric | Billed and Unbilled Revenue |  |  |  |
Operating Revenues [Line Items] |  |  |  |
Total Gas and Electric Operating Revenues | $ 1.5 | $ 2.1 | $ 3.5 | $ 4.3

X
- Definition Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 41 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130545-203045 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 30 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130543-203045 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 40 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 924 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 11.L) -URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856 + Details
Name: | us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | utl_OperatingRevenuesLineItems
Namespace Prefix: | utl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis=utl_BilledAndUnbilledRevenueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivablesByBillingStatusTypeAxis=utl_RateAdjustmentMechanismRevenueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=utl_GasSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=utl_ElectricMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=utl_ResidentialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=utl_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=us-gaap_OtherCustomerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |