Revenue Recognition (Schedule Of Disaggregated Revenue) (Details) - Roto-Rooter [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Subtotal	$ 196,067	$ 162,888	$ 558,030	$ 488,299
Implicit price concessions and credit memos	(4,867)	(4,023)	(14,213)	(13,347)
Net revenue	191,200	158,865	543,817	474,952
Short-Term Core Service Jobs [Member]
Subtotal	143,089	116,277	404,054	344,673
Water Restoration [Member]
Subtotal	32,137	27,642	92,810	86,804
Contractor Revenue [Member]
Subtotal	16,274	14,359	47,695	42,986
Franchise Fees [Member]
Subtotal	1,235	1,819	3,635	5,063
All Other [Member]
Subtotal	$ 3,332	$ 2,791	$ 9,836	$ 8,773