Revenue Recognition (Schedule Of Disaggregated Revenue) (Details) - Roto-Rooter [Member] - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Subtotal	$ 177,341	$ 165,357	$ 361,963	$ 325,411
Implicit price concessions and credit memos	(2,607)	(4,523)	(9,346)	(9,324)
Net revenue	174,734	160,834	352,617	316,087
Short-Term Core Service Jobs [Member]
Subtotal	126,541	116,211	260,965	228,397
Water Restoration [Member]
Subtotal	31,426	29,955	60,672	59,163
Contractor Revenue [Member]
Subtotal	15,193	14,595	31,421	28,627
Franchise Fees [Member]
Subtotal	1,210	1,623	2,400	3,245
All Other [Member]
Subtotal	$ 2,971	$ 2,973	$ 6,505	$ 5,979

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration