Revenue Recognition (Schedule Of Disaggregated Revenue) (Details) - Roto-Rooter [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Subtotal	$ 225,429	$ 177,341	$ 442,245	$ 361,963
Implicit price concessions and credit memos	(5,108)	(2,607)	(10,352)	(9,346)
Net revenue	220,321	174,734	431,893	352,617
Short-Term Core Service Jobs [Member]
Subtotal	162,683	126,541	318,032	260,965
Water Restoration [Member]
Subtotal	38,583	31,426	76,018	60,672
Contractor Revenue [Member]
Subtotal	19,026	15,193	37,785	31,421
Franchise Fees [Member]
Subtotal	1,255	1,210	2,582	2,400
All Other [Member]
Subtotal	$ 3,882	$ 2,971	$ 7,828	$ 6,505