Acquisitions (Schedule Of Business Acquisitions Revenue And Net Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Service revenue and sales	$ 1,938,555	$ 1,782,648	$ 1,666,724
Net income/(loss)	219,923	205,544	$ 98,177
HSW RR, Inc [Member]
Business Acquisition [Line Items]
Service revenue and sales	20,141	1,782
Net income/(loss)	(2,777)
Roto-Rooter, Oakland [Member]
Business Acquisition [Line Items]
Service revenue and sales	5,150	95
Net income/(loss)	231
HSW And Oakland [Member]
Business Acquisition [Line Items]
Service revenue and sales	25,291	$ 1,877
Net income/(loss)	$ (2,546)