Revenue Recognition (Schedule Of Disaggregated Revenue) (Details) - Roto-Rooter [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Subtotal	$ 216,817	$ 184,622
Implicit price concessions and credit memos	(5,245)	(6,740)
Net revenue	211,572	177,882
Short-Term Core Service Jobs [Member]
Subtotal	155,350	134,424
Water Restoration [Member]
Subtotal	37,435	29,246
Contractor Revenue [Member]
Subtotal	18,760	16,228
Franchise Fees [Member]
Subtotal	1,327	1,190
All Other [Member]
Subtotal	$ 3,945	$ 3,534