XML 61 R49.htm IDEA: XBRL DOCUMENT v3.23.2

Restricted Stock Units Issued (Detail) - Restricted Stock Units (RSUs)	6 Months Ended
	Jun. 30, 2023 $ / shares shares
Restricted Stock Units
Beginning Restricted Stock Units | shares	43,799
Restricted Stock Units Granted | shares	0
Dividend Equivalents Earned | shares	669
Restricted Stock Units Settled | shares	0
Ending Restricted Stock Units | shares	44,468
Weighted-Average Stock Price
Beginning Restricted Stock Units | $ / shares	$ 40.17
Restricted Stock Units Granted | $ / shares	0
Dividend Equivalents Earned | $ / shares	53.24
Restricted Stock Units Settled | $ / shares	0
Ending Restricted Stock Units | $ / shares	$ 40.37

X

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(01)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other than Options, Fully Vested Grants in Period, Weighted Average Grant Date Fair Value.

+ References

No definition available.

+ Details

Name:	utl_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFullyVestedGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	utl_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Fully Vested Settled.

+ References

No definition available.

+ Details

Name:	utl_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFullyVestedSettled
Namespace Prefix:	utl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other than Options, Fully Vested Settled in Period, Weighted Average Grant Date Fair Value.

+ References

No definition available.

+ Details

Name:	utl_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFullyVestedSettledInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	utl_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other than Options, Fully Vested, Weighted Average Grant Date Fair Value

+ References

No definition available.

+ Details

Name:	utl_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFullyVestedWeightedAverageGrantDateFairValue
Namespace Prefix:	utl_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Share Based Payment Award Equity Instruments Other Than Options Dividend Equivalent Rights In Period.

+ References

No definition available.

+ Details

Name:	utl_ShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsDividendEquivalentRightsInPeriod
Namespace Prefix:	utl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share Based Payment Award Equity Instruments Other Than Options Fully Vested Dividend Equivalent Rights In Period Weighted Average Grant Date Fair Value.

+ References

No definition available.

+ Details

Name:	utl_ShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsFullyVestedDividendEquivalentRightsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	utl_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Share-Based Compensation Arrangement by Share-Based Payment Award, Equity Instruments Other than Options, Fully Vested, Number

+ References

No definition available.

+ Details

Name:	utl_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsFullyVestedNumber
Namespace Prefix:	utl_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: