Fair Value Measurements - Summary of Qualitative Information About Level 3 Fair Value Measurements (Details) - Fair Value Level 3 [Member] $ in Millions	Mar. 26, 2021 USD ($)
EBITDA Multiple [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.055
EBITDA Multiple [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.074
Discount Rate [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.155
Discount Rate [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.200
Rate on Return [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.024
Salary Increase Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.040
Common Stock Purchase Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration	$ 12.6
Business Combination Contingent Consideration Liability Valuation Technique Extensible List	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Common Stock Purchase Obligation [Member] | Revenue Multiple [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.013
Common Stock Purchase Obligation [Member] | Revenue Multiple [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.017
Pension Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration	$ 5.0
Pension Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Business Combination Contingent Consideration Liability Valuation Technique Extensible List	uctt:ValuationTechniqueProjectedUnitCreditMethodMember
Pension Obligation [Member] | Discount Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range/Multiple	0.021