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Overview and Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jan. 31, 2023 robux	Jan. 31, 2022 robux	Jan. 30, 2022 robux
Disaggregation of Revenue [Line Items]
Average lifetime of a paying user	27 months			28 months
Increase (decrease) in revenue		$ 98,000,000
Cost of revenue		20,400,000
Restricted cash		$ 0	$ 0
Payment remittance term (within) (in days)		30 days
Intangible asset, useful life (in years)		5 years 4 months 24 days
Developer exchange program, minimum virtual currency earned requirement \| robux					30,000	50,000	100,000
Advertising cost		$ 79,200,000	45,400,000	$ 38,300,000
Operating lease, renewal term (up to) (in years)		5 years
Net foreign exchange gains (losses)		$ 2,100,000	$ (14,100,000)	$ (2,000,000.0)
Employee \| NQDC Plan
Disaggregation of Revenue [Line Items]
Maximum of salary (in percent)		90.00%
Maximum granted (in percent)		100.00%
Maximum of cash bonus compensation (in percent)		65.00%
Non-Employee Director Member \| NQDC Plan
Disaggregation of Revenue [Line Items]
Maximum of salary (in percent)		100.00%
RSUs outstanding
Disaggregation of Revenue [Line Items]
Vesting period		4 years
Three Payment Processors \| Accounts Receivable \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Revenue (in percent)		67.00%	69.00%
One Payment Processor \| Revenue Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Revenue (in percent)		29.00%	30.00%	30.00%
Second Payment Processor \| Revenue Benchmark \| Customer Concentration Risk
Disaggregation of Revenue [Line Items]
Revenue (in percent)		15.00%	16.00%	17.00%
Minimum
Disaggregation of Revenue [Line Items]
Intangible asset, useful life (in years)		5 years
Maximum
Disaggregation of Revenue [Line Items]
Intangible asset, useful life (in years)		10 years
Operating lease term (in years)		12 years