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Retirement Benefit Obligations - Additional Information (Detail) (USD $) | 6 Months Ended
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Jun. 30, 2013
Pension Plan |
Defined Benefit Plan Disclosure [Line Items] |
Contributions to benefit plan | $ 0
Other Postretirement Benefit Plans, Defined Benefit |
Defined Benefit Plan Disclosure [Line Items] |
Contributions to benefit plan | 0
Supplemental Employee Retirement Plans, Defined Benefit |
Defined Benefit Plan Disclosure [Line Items] |
Contributions to benefit plan | 26,000
Expected additional contribution to SERP plan | $ 27,000

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- Definition The increase in the fair value of plan assets from contributions made by the employer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Details
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Balance Type: | na
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- Definition Defined Benefit Plan, Estimated Additional Employer Contributions in Remainder Of Fiscal Year + References No definition available. + Details
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Namespace Prefix: | utl_
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