Nature of Operations and Summary of Significant Accounting Policies - Clinics in Operation Under Franchise Agreements or Company-owned or Managed (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2026 clinic license	Jun. 30, 2025 clinic license	Jun. 30, 2026 clinic license	Jun. 30, 2025 clinic license
Product Information, Franchised Clinics, Company-Owned Or Managed Clinics, Activity [Roll Forward]
Clinics in operation at the end of the period	941	967	941	967
Clinic licenses sold but not yet developed at the end of the period \| license	52	92	52	92
Future clinic licenses subject to executed letters of intent at the end of the period \| license	58	60	58	60
Franchised Clinics
Product Information, Franchised Clinics, Company-Owned Or Managed Clinics, Activity [Roll Forward]
Clinics open at the beginning of the period	868	847	885	842
Opened during the period	5	7	8	12
Acquired during the period	29	37	29	39
Closed during the period	(6)	(6)	(26)	(8)
Clinics in operation at the end of the period	896	885	896	885
Company-owned or managed clinics: \| Discontinued Operations, Held-for-Sale or Disposed of by Sale \| Corporate Clinics
Product Information, Franchised Clinics, Company-Owned Or Managed Clinics, Activity [Roll Forward]
Clinics open at the beginning of the period	75	122	75	125
Sold during the period	(29)	(37)	(29)	(39)
Closed during the period	(1)	(3)	(1)	(4)
Clinics in operation at the end of the period	45	82	45	82