EMPLOYEE BENEFIT PLANS - Schedule of Stock-Based Compensation Expense in the Consolidated Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 39.6	$ 23.8	$ 59.9	$ 48.0
Income Statement Location [Axis]: us-gaap:CostOfRevenue
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	1.0	0.6	1.6	1.3
Income Statement Location [Axis]: us-gaap:GeneralAndAdministrativeExpense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	6.9	8.8	14.1	20.4
Income Statement Location [Axis]: us-gaap:ResearchAndDevelopmentExpense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	9.2	8.9	16.8	17.5
Income Statement Location [Axis]: us-gaap:SellingAndMarketingExpense
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	6.7	5.5	11.6	10.4
Income Statement Location [Axis]: cour:MergerIntegrationAndRestructuringRelatedCosts
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 15.8	$ 0.0	$ 15.8	$ (1.6)

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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