Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Net loss	$ (57,591)	$ (19,856)
Other comprehensive loss:
Foreign currency translation (loss) income	(79)	13
Comprehensive loss	(57,670)	(19,843)
Comprehensive loss attributable to non-controlling interest	(10,538)	(3,971)
Comprehensive loss attributable to System1, Inc.	$ (47,132)	$ (15,872)

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.

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

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- Definition

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

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- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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