Summary Of Significant Accounting Policies (Weighted Average Lives Of Identifiable, Definite-Lived Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2020
Non-Compete Agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average lives of identifiable, definite-lived intangible assets	6 years 6 months
Reacquired Franchise Rights [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average lives of identifiable, definite-lived intangible assets	7 years 4 months 24 days
Referral Networks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average lives of identifiable, definite-lived intangible assets	10 years
Customer Lists [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average lives of identifiable, definite-lived intangible assets	16 years 9 months 18 days