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Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
	Jun. 30, 2025	Jun. 30, 2026	Jun. 24, 2025	Mar. 29, 2025	Jun. 30, 2026	Jun. 24, 2025	May 01, 2026	Dec. 31, 2025	Jun. 25, 2025	Dec. 28, 2024
Goodwill And Intangible Assets Disclosure [Line Items]
Goodwill		$ 199,910	$ 199,053		$ 199,910	$ 199,053		$ 200,135	$ 199,053	$ 239,583
Finite-lived intangible assets, aggregate amortization expense	$ 1,623	$ 25,325	$ 6,455		$ 50,591	$ 12,405
Behavioral Reporting Unit
Goodwill And Intangible Assets Disclosure [Line Items]
Percentage of goodwill held							81.00%
Behavioral Reporting Unit \| Maximum
Goodwill And Intangible Assets Disclosure [Line Items]
Percentage of estimated fair value in excess of carrying amount							10.00%
Clinical Reporting Unit
Goodwill And Intangible Assets Disclosure [Line Items]
Percentage of goodwill held							19.00%
Trade Name \| Maximum
Goodwill And Intangible Assets Disclosure [Line Items]
Percentage of estimated fair value of asset in excess of carrying amount							10.00%
Franchise rights acquired \| United States
Goodwill And Intangible Assets Disclosure [Line Items]
Indefinite-lived intangible assets, impairment charges				$ 27,549
Indefinite-lived franchise rights acquired percentage				100.00%
Impairment, Intangible Asset, Indefinite-Lived (Excluding Goodwill), Statement of Income or Comprehensive Income [Extensible Enumeration]				Asset Impairment Charges