Percentage of employees eligible compensation.

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Percentage of number of shares of capital stock outstanding on last day of preceding year.

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Share-based compensation arrangement by share-based payment award, offering period.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Aggregate number of common shares reserved for future issuance.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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Amount of cost to be recognized for option under share-based payment arrangement.

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Discount rate from fair value on offering date that participants pay for shares.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The highest quantity of shares an employee can purchase under the plan per period.

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Gross number of share options (or share units) granted during the period.

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Description of terms of award under share-based payment arrangement.

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Number of options vested.

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Equity-Based Compensation - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 17, 2025	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024	Jul. 25, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Equity-based compensation expense		$ 31,434	$ 2,719	$ 69,343	$ 3,832
2024 Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized equity-based compensation cost, weighted-average remaining service period				3 years 1 month 6 days
Unrecognized equity-based compensation expense		11,500		$ 11,500
2019 Common Unit Option Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized equity-based compensation cost, weighted-average remaining service period				2 years 3 months 18 days
Unrecognized equity-based compensation expense		53,100		$ 53,100
Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Consecutive offering periods				The Company’s board of directors amended and restated the ESPP in January 2025 to provide for consecutive offering periods lasting approximately 24 months and consisting of four purchase periods of approximately six months. An offering period generally starts on the first trading day on or after May 15 and November 15 of each year and ends on the last trading day of the applicable 24-month period. The initial offering period under the ESPP commenced on February 17, 2025 and will extend through the first trading day on or after May 15, 2027.
Offering period				24 months
Percentage of employees eligible compensation	0.15
Maximum number of shares per employee	3,000
Unrecognized equity-based compensation expense		3,900		$ 3,900
Unrecognized equity-based compensation cost, weighted-average remaining service period				1 year 10 months 24 days
Equity-based compensation expense		$ 600		$ 600
Percentage of number of shares of capital stock outstanding on last day of preceding year				1.00%
Class A common stock \| Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Percentage purchase price of shares equal to fair market value	85.00%
Common stock reserved for future issuance		5,400,000		5,400,000
Class A common stock \| Employee Stock Purchase Plan \| Initial Public Offering \| OneStream Software LLC
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock reserved for future issuance							10,700,000
Performance-based Shares \| DataSense
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized equity-based compensation expense		$ 6,600		$ 6,600
Unrecognized equity-based compensation cost, weighted-average remaining service period				1 year 4 months 24 days
Performance-based Shares \| DataSense \| Class C common stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common units vested				302,791
Options granted				706,511		1,009,302
RSUs
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Unrecognized equity-based compensation expense		$ 132,000		$ 132,000
Unrecognized equity-based compensation cost, weighted-average remaining service period				3 years 8 months 12 days