Fair Value - Additional Information (Detail) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Increase in fair value	$ 250,000
Derivative instrument maximum maturity period	30 years
Transfers between level 1 and level 2	$ 0	$ 0
Transfers between level 2 and level 3	0	0
Fair value of the collateral dependent loans, net carrying amount	1,700,000	4,000,000
Specific allowance for collateral dependent loans	$ 491,000	1,300,000
Discount applied to appraisals for estimated selling costs percentage	10.00%
Mortgage servicing rights additions charged to (recovery) expense	$ 9,000	(39,000)	$ (19,000)
Other real estate owned carried at fair value	436,000	1,000,000
Valuation allowance related to other real estate owned	403,000	1,000,000
Additions (recoveries) charged to expense	37,000	(16,000)	287,000
Gains (losses) from changes in fair value included in earnings	$ 3,893,000	(1,769,000)	1,519,000
Maximum maturity period of short term borrowings	90 days
Collateral Dependent Loans [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Increase (decrease) in provision for loan losses	$ 938,000	4,100,000
Mortgage Servicing Rights [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Mortgage servicing rights	382,000	0
Construction [Member] \| Loans Held For Sale [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Gains (losses) from changes in fair value included in earnings	3,900,000	(1,800,000)	$ 1,500,000
Construction [Member] \| Fair Value, Measurements, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value option, loans held as assets, aggregate amount in nonaccrual status	0	0
Interest Rate Caps [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate caps	$ 0	$ 0

Derivative instrument maximum maturity period.

No definition available.

Name:	ucfc_DerivativeInstrumentMaximumMaturityPeriod
Namespace Prefix:	ucfc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Discount applied to appraisals for estimated selling costs percentage.

+ References

No definition available.

+ Details

Name:	ucfc_DiscountAppliedToAppraisalsForEstimatedSellingCostsPercentage
Namespace Prefix:	ucfc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value, assets and liabilities, level one to (from) level two, transfer amount.

+ References

No definition available.

+ Details

Name:	ucfc_FairValueAssetsAndLiabilitiesLevelOneToFromLevelTwoTransferAmount
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value, assets and liabilities, level two to (from) level three, transfer amount.

+ References

No definition available.

+ Details

Name:	ucfc_FairValueAssetsAndLiabilitiesLevelTwoToFromLevelThreeTransferAmount
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Impaired loans collateral dependent.

+ References

No definition available.

+ Details

Name:	ucfc_ImpairedLoansCollateralDependent
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Maximum maturity period of short term borrowings.

+ References

No definition available.

+ Details

Name:	ucfc_MaximumMaturityPeriodOfShortTermBorrowings
Namespace Prefix:	ucfc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Other real estate owned carried at fair value.

+ References

No definition available.

+ Details

Name:	ucfc_OtherRealEstateOwnedCarriedAtFairValue
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Real estate owned minimum fair value for appraisal.

+ References

No definition available.

+ Details

Name:	ucfc_RealEstateOwnedMinimumFairValueForAppraisal
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Real estate owned valuation allowance provision (recovery).

+ References

No definition available.

+ Details

Name:	ucfc_RealEstateOwnedValuationAllowanceProvisionRecovery
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Specific allowance for collateral dependent loans.

+ References

No definition available.

+ Details

Name:	ucfc_SpecificAllowanceForCollateralDependentLoans
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Valuation allowance related to other real estate owned.

+ References

No definition available.

+ Details

Name:	ucfc_ValuationAllowanceRelatedToOtherRealEstateOwned
Namespace Prefix:	ucfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of increase (decrease) of allowance reserve for credit loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_AllowanceForLoanAndLeaseLossesPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

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

- Definition

For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14172-108612

+ Details

Name:	us-gaap_FairValueOptionChangesInFairValueGainLoss1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the aggregate fair value of loans held as assets that are in nonaccrual status for which the fair value option has been elected, if the entity's policy is to recognize interest income separately from other changes in fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (e)(2)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

+ Details

Name:	us-gaap_FairValueOptionLoansHeldAsAssetsAggregateAmountInNonaccrualStatus
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

+ Details

Name:	us-gaap_InterestRateDerivativeAssetsAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The adjustment to the carrying value of the rights retained or purchased to service mortgages. These adjustments are made when the estimate of the fair value is changed. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(6),(7)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122739-111746

+ Details

Name:	us-gaap_MortgageServicingRightsMSRImpairmentRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746

+ Details

Name:	us-gaap_ServicingAssetAtFairValueAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ucfc_CollateralDependentLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ucfc_MortgageServicingRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=ucfc_LoansHeldForSaleAtFairValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateCapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: