Debt Instrument, Extension Term

No definition available.

Name:	uctt_DebtInstrumentExtensionTerm
Namespace Prefix:	uctt_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Interest Rate, Stated Percentage, Reduction

+ References

No definition available.

+ Details

Name:	uctt_DebtInstrumentInterestRateStatedPercentageReduction
Namespace Prefix:	uctt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Issuance Costs, Gross, Previously Capitalized

+ References

No definition available.

+ Details

Name:	uctt_DebtIssuanceCostsGrossPreviouslyCapitalized
Namespace Prefix:	uctt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt Issuance Costs, Lender Fees

+ References

No definition available.

+ Details

Name:	uctt_DebtIssuanceCostsLenderFees
Namespace Prefix:	uctt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Payment For Extinguishment Of Bank Borrowings

+ References

No definition available.

+ Details

Name:	uctt_PaymentForExtinguishmentOfBankBorrowings
Namespace Prefix:	uctt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage Of Original Outstanding Principal Balance As Quarterly Principal Payment

+ References

No definition available.

+ Details

Name:	uctt_PercentageOfOriginalOutstandingPrincipalBalanceAsQuarterlyPrincipalPayment
Namespace Prefix:	uctt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage Of Outstanding Principal Balance, Interest Rate Reduction

+ References

No definition available.

+ Details

Name:	uctt_PercentageOfOutstandingPrincipalBalanceInterestRateReduction
Namespace Prefix:	uctt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage Of Undrawn And Unexpired Amount Of Letter Of Credit As Fronting Fee

+ References

No definition available.

+ Details

Name:	uctt_PercentageOfUndrawnAndUnexpiredAmountOfLetterOfCreditAsFrontingFee
Namespace Prefix:	uctt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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.

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+ Details

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

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

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- 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

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Data Type:	xbrli:monetaryItemType
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- Definition

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

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- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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Balance Type:	credit
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- Definition

The cash inflow from bank borrowing during the year.

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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

No definition available.

+ Details

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Borrowing Arrangements - Additional Information (Details) € in Millions, $ in Millions				12 Months Ended
	Sep. 15, 2025	Oct. 08, 2024	Apr. 04, 2024 USD ($)	Dec. 26, 2025 USD ($)	Dec. 27, 2024 USD ($)	Dec. 29, 2023 USD ($)	Dec. 26, 2025 EUR (€)	Apr. 03, 2024 USD ($)
Debt Instrument [Line Items]
Proceeds from bank borrowings				$ 59.3	$ 67.7	$ 0.0
Extinguishment of bank borrowings				59.3	44.2	$ 0.0
Amortization of debt issuance costs					$ 3.6
Total bank debt				481.4
Bank Debt
Debt Instrument [Line Items]
Unamortized debt issuance costs				4.5
Total bank debt				476.9
Secured Debt \| Term Loan Credit Facility
Debt Instrument [Line Items]
Proceeds from bank borrowings			$ 67.7
Lender fees			1.1
Extinguishment of bank borrowings			44.2
Debt issuance costs			2.5
Deferred capitalize debt costs			$ 5.2
Secured Debt \| Term Loan Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Extended maturity date period			30 months
Debt instrument, interest rate reduction	0.50%		0.25%
Outstanding debt			$ 500.0	481.4				$ 475.4
Term Loan Credit Facility
Debt Instrument [Line Items]
Percentage of original outstanding balance, additional reduction		0.25%
Percentage of original outstanding principal balance as quarterly principal payment	0.625%
Unamortized debt issuance costs				$ 4.5
Term loan, interest rate				6.70%			6.70%
Term Loan Credit Facility \| Minimum \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument variable interest rate		2.50%
Term Loan Credit Facility \| Minimum \| Base Rate
Debt Instrument [Line Items]
Debt instrument variable interest rate		1.50%
Term Loan Credit Facility \| Maximum \| Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Debt instrument variable interest rate		2.75%
Term Loan Credit Facility \| Maximum \| Base Rate
Debt Instrument [Line Items]
Debt instrument variable interest rate		1.75%
Revolving Credit Facility
Debt Instrument [Line Items]
Initial available commitment				$ 150.0
Commitment fee percentage				0.25%
Remaining available commitments				$ 146.6
Outstanding amount under credit facility				3.4
Revolving Credit Facility \| Bank Debt
Debt Instrument [Line Items]
Initial available commitment				8.2
Revolving Credit Facility \| Bank Debt \| Czech Republic
Debt Instrument [Line Items]
Initial available commitment \| €							€ 7.0
Remaining available commitments				6.5
Revolving Credit Facility \| Bank Debt \| United States
Debt Instrument [Line Items]
Remaining available commitments				146.6
Revolving Credit Facility \| Bank Debt \| Israel
Debt Instrument [Line Items]
Remaining available commitments				5.0
Letter of Credit Facility
Debt Instrument [Line Items]
Initial available commitment				50.0
Remaining available commitments				46.6
Outstanding amount under credit facility				$ 3.4
Percentage of undrawn and unexpired amount of letter of credit as fronting fee				0.125%
Fluid Solutions
Debt Instrument [Line Items]
Initial available commitment				$ 5.0