Summary of Significant Accounting Policies (Details) $ in Thousands		3 Months Ended	9 Months Ended
	Aug. 20, 2026 USD ($)	Sep. 30, 2026 USD ($)	Sep. 30, 2026 USD ($) segment shares	Dec. 31, 2025 USD ($)
Product Information [Line Items]
Carrying amount		$ 600	$ 600	$ 200
Loss exposure, amount		7,300	$ 7,300	6,900
Number of operating segments | segment			1
Number of reportable segments | segment			1
Tax Receivable Agreement liability	$ 74,400	74,363	$ 74,363	$ 0
Tax receivable, benefit percentage	85.00%
Establishment of liabilities under Tax Receivable Agreement and related changes to deferred tax assets associated with increases in tax basis	$ 13,100	(13,136)	$ (13,136)
AT Umbrella LLC
Product Information [Line Items]
Deferred tax assets	$ 87,500
Class A Common Stock
Product Information [Line Items]
Shares issued on exchange of units (in shares) | shares			5,029,125
Class X Umbrella Units
Product Information [Line Items]
Shares converted (in shares) | shares			5,029,125
Class X Umbrella Units | Resale Offering, Selling Stockholders
Product Information [Line Items]
Shares converted (in shares) | shares			4,927,125
Tax Receivables Agreement
Product Information [Line Items]
Payments for tax receivable agreement		$ 0	$ 0
Andersen Tax Holdings LLC
Product Information [Line Items]
Ownership percentage		100.00%	100.00%