Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 27, 2019	Sep. 28, 2018	Sep. 27, 2019	Sep. 28, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 888	$ (6,440)	$ 1,988	$ 37,261
Other comprehensive income (loss):
Change in cumulative translation adjustment	(1,626)	(193)	(3,780)	(656)
Cash flow hedges:
Change in fair value of derivatives	(44)	39	48	(24)
Adjustment for net loss realized and included in net loss	(24)	(337)	(70)	(1,247)
Total change in unrealized loss on derivative instruments	(68)	(298)	(22)	(1,271)
Other comprehensive loss, net of tax	(1,694)	(491)	(3,802)	(1,927)
Comprehensive income (loss)	(806)	(6,931)	(1,814)	35,334
Less: Comprehensive income (loss) attributable to noncontrolling interest	375	(37)	1,072	(37)
Comprehensive income (loss) attributable to Ultra Clean Holdings, Inc.	$ (1,181)	$ (6,894)	$ (2,886)	$ 35,371

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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