Fair Value Measurements - Summary of Qualitative Information About Level 3 Fair Value Measurements (Details) - Fair Value Level 3 [Member] $ in Millions	Mar. 27, 2020 USD ($)
Revenue Discount Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.075
Revenue volatility Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.410
Rate On Return [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.015
Measurement Input, EBITDA Multiple
Defined Benefit Plan Disclosure [Line Items]
Range	0.050
Salary Increase Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.045
Common Stock Purchase Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration	$ 7.0
Business Combination Contingent Consideration Liability Valuation Technique Extensible List	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Common Stock Purchase Obligation [Member] | Revenue Discount Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.013
Pension Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration	$ 4.9
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	0.020
Contingent Earn-out Liability [Member]
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration	$ 12.3
Business Combination Contingent Consideration Liability Valuation Technique Extensible List	uctt:ValuationTechniqueMonteCarloSimulationMember