XML 41 R27.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Components of Accrued Revenue (Detail) - USD ($) $ in Millions | Jun. 30, 2016 | Dec. 31, 2015 | Jun. 30, 2015
--- | --- | --- | ---
Deferred Revenue Arrangement [Line Items] |  |  |
Accrued Revenue | $ 31.9 | $ 38.4 | $ 28.6
Unbilled Revenues |  |  |
Deferred Revenue Arrangement [Line Items] |  |  |
Accrued Revenue | 6.7 | 11.6 | 6.0
Regulatory Assets |  |  |
Deferred Revenue Arrangement [Line Items] |  |  |
Accrued Revenue | $ 25.2 | $ 26.8 | $ 22.6

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_DeferredRevenueArrangementLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unbilled amounts due for services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the entity and, at a minimum, one other party. An example would be amounts associated with contracts or programs where the recognized revenue for performance thereunder exceeds the amounts billed under the terms thereof as of the date of the balance sheet. + 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 210.5-02.3(c)(3)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 912 -SubTopic 310 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=68054760&loc=d3e55302-109406 + Details
Name: | us-gaap_UnbilledContractsReceivable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=utl_RegulatoryAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |