Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands		3 Months Ended			9 Months Ended		12 Months Ended
		Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Mar. 31, 2022	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2021	Jan. 31, 2023 robux	Jan. 31, 2022 robux	Jan. 30, 2022 robux
Disaggregation of Revenue [Line Items]
Average lifetime of a paying user		28 months	28 months	25 months	28 months		23 months
Decrease in revenue		$ 713,225	$ 517,707		$ 2,049,335	$ 1,646,048
Decrease in cost of revenue	[1]	$ 163,581	126,437		$ 477,451	405,226
Developer exchange program, minimum virtual currency earned requirement | robux								30,000	50,000	100,000
Service Life
Disaggregation of Revenue [Line Items]
Decrease in revenue			(111,000)			(329,700)
Decrease in cost of revenue			$ (25,500)			$ (76,400)

[1] Depreciation of servers and infrastructure equipment included in infrastructure and trust & safety.