Commitments and Contingencies (Details) $ in Thousands	9 Months Ended
Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Commitments and Contingencies [Abstract]
Self Insurance Reserve	$ (84,700)	$ (78,000)
Litigation Settlement, Expense	15,000
Insurance Settlements Receivable	$ 3,500
Number Of States Involved In Litigation	36

Carrying amount (including both current and noncurrent portions) of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_SelfInsuranceReserve
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant