Equity-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		12 Months Ended
	Dec. 06, 2025	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		$ 45,604	$ 0
Cost of services
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		41,226	0
Sales, general and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		$ 4,378	$ 0
AT Umbrella LLC LTIP Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage		20.00%
Granted, weighted average grant date fair value (in dollars per share)		$ 16.00
Unamortized compensation cost not yet recognized		$ 12,900
Weighted-average period cost not yet recognized		4 years 8 months 12 days
Annual anniversary of the vesting commencement		5 years
Issuance of threshold (in dollars per share)				$ 16.00
AT Umbrella LLC LTIP Units | Cost of services
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		$ 900
Class X Aggregator Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage		20.00%
Granted, weighted average grant date fair value (in dollars per share)		$ 16.00
Compensation expenses		$ 41,100
Unamortized compensation cost not yet recognized		$ 662,200
Weighted-average period cost not yet recognized		4 years 6 months
Class X Aggregator Units | Cost of services
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		$ 37,500
Class X Aggregator Units | Sales, general and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		$ 3,600
2025 Equity Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Common stock reserved for issuance (in shares)		12,290,828
Shares outstanding percentage	5.00%
Annual shares authorized increase, percent of outstanding shares (in shares)	0
2025 Equity Incentive Plan | Restricted Stock Units (RSUs)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting percentage		16.70%
Granted, weighted average grant date fair value (in dollars per share)	$ 16.00
Compensation expenses		$ 3,600
Unamortized compensation cost not yet recognized		$ 78,400
Weighted-average period cost not yet recognized		5 years 8 months 12 days
2025 Equity Incentive Plan | Restricted Stock Units (RSUs) | Cost of services
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		$ 2,800
2025 Equity Incentive Plan | Restricted Stock Units (RSUs) | Sales, general and administrative
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Compensation expenses		$ 800