Debt Instrument, Conversion Premium

No definition available.

Name:	uis_DebtInstrumentConversionPremium
Namespace Prefix:	uis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Convertible, Conversion Rate

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentConvertibleConversionRate
Namespace Prefix:	uis_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Change in Control, Redemption Price, Percentage

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantChangeinControlRedemptionPricePercentage
Namespace Prefix:	uis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Collateral Coverage Ratio, Calculation, Amount Added to Cash and Cash Equivalents

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantCollateralCoverageRatioCalculationAmountAddedtoCashandCashEquivalents
Namespace Prefix:	uis_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Collateral Coverage Ratio Calculation, Average Grantor EBITDA Multiplier for Seven Most Recent Fiscal Quarters

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantCollateralCoverageRatioCalculationAverageGrantorEBITDAMultiplierforSevenMostRecentFiscalQuarters
Namespace Prefix:	uis_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Collateral Coverage Ratio, Minimum

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantCollateralCoverageRatioMinimum
Namespace Prefix:	uis_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Minimum Fixed Charge Coverage Ratio, Available Borrowings Threshold

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantMinimumFixedChargeCoverageRatioAvailableBorrowingsThreshold
Namespace Prefix:	uis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Covenant, Minimum Fixed Charge Coverage Ratio, Available Borrowings Threshold, Percent of Lender Commitments

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantMinimumFixedChargeCoverageRatioAvailableBorrowingsThresholdPercentofLenderCommitments
Namespace Prefix:	uis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Required Collateral Coverage Ratio Not Met, Redemption Period

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantRequiredCollateralCoverageRatioNotMetRedemptionPeriod
Namespace Prefix:	uis_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Required Collateral Coverage Ratio Not Met, Redemption Price, Percentage

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentCovenantRequiredCollateralCoverageRatioNotMetRedemptionPricePercentage
Namespace Prefix:	uis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Debt Default, Triggering Event Threshold, Amount

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentDebtDefaultTriggeringEventThresholdAmount
Namespace Prefix:	uis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Redemption, Percentage of Notes

+ References

No definition available.

+ Details

Name:	uis_DebtInstrumentRedemptionPercentageofNotes
Namespace Prefix:	uis_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

Name:	uis_LineofCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	uis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Springing Maturity Date, Period Prior to Maturity Date of Convertible Debt

+ References

No definition available.

+ Details

Name:	uis_LineofCreditFacilitySpringingMaturityDatePeriodPriortoMaturityDateofConvertibleDebt
Namespace Prefix:	uis_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Springing Maturity Date, Period Prior to Maturity Date of Secured Debt

+ References

No definition available.

+ Details

Name:	uis_LineofCreditFacilitySpringingMaturityDatePeriodPriortoMaturityDateofSecuredDebt
Namespace Prefix:	uis_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Payments for Capped Call Transactions

+ References

No definition available.

+ Details

Name:	uis_PaymentsForCappedCallTransactions
Namespace Prefix:	uis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The price per share of the conversion feature embedded in the debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031898-161870

+ Details

Name:	us-gaap_DebtInstrumentConvertibleConversionPrice1
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of equity instruments that the holder of the debt instrument would receive if the debt was converted to equity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(5))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentConvertibleNumberOfEquityInstruments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 6
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6036836-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateEffectivePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=uis_ConvertibleSeniorNotesDue2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=uis_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=uis_SeniorSecuredNotesDue2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Debt - Additional Information (Detail)	12 Months Ended
Debt - Additional Information (Detail)	Dec. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) shares $ / shares	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)
Debt Instrument [Line Items]
Payments for capped call transactions	$ 0	$ 0	$ 27,300,000
Convertible Senior Notes due 2021
Debt Instrument [Line Items]
Aggregate principal amount			1,000
Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 145,000,000	$ 125,000,000.0
Accordion feature increase limit	150,000,000
Borrowings outstanding	0
Availability under the facility, net of letters of credit issued	$ 138,500,000
Springing maturity, period prior to maturity date of convertible senior notes due 2021	91 days
Springing maturity, period prior to maturity date of secured notes due 2022	60 days
Credit Agreement \| Letters of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 30,000,000.0
Letters of credit outstanding	$ 6,500,000
Senior Notes \| Senior Secured Notes due 2022
Debt Instrument [Line Items]
Aggregate principal amount		$ 440,000,000
Interest rate		10.75%
Redemption price, percent of principal amount of notes redeemed		100.00%
Percent of notes with option to redeem		35.00%
Redemption price, percentage of principal amount		110.75%
Redemption price if required collateral coverage ratio not met, percentage of principal amount		100.00%
Minimum collateral coverage ratio		1.5
Collateral coverage ratio, amount added to cash and cash equivalents		4.75
Collateral coverage ratio, multiplier for Average Grantor EBITDA for seven most recent fiscal quarters		4
Period to redeem notes without default if required collateral coverage ratio not met		90 days
Redemption price if company experiences change of control, percent of principal amount		101.00%
Senior Notes \| Convertible Senior Notes due 2021
Debt Instrument [Line Items]
Aggregate principal amount	$ 213,500,000.0	$ 213,500,000.0	$ 213,500,000.0
Interest rate	5.50%		5.50%
Effective interest rate			9.50%
Conversion rate (in shares) \| shares			102.4249
Total amount of conversion (in shares) \| shares			21,867,716
Conversion price (in usd per share) \| $ / shares	$ 12.75		$ 9.76
Payments for capped call transactions			$ 27,300,000
Conversion premium	60.00%		22.50%
Line of Credit \| Credit Agreement \| Revolving Credit Facility
Debt Instrument [Line Items]
Requirement to maintain fixed charge coverage ratio, availability threshold, percent of lender commitments under facility	10.00%
Requirement to maintain fixed charge coverage ratio, availability threshold	$ 15,000,000
Amount of aggregate default under other debt that would trigger event of default	$ 50,000,000